LibreJS 1 Overview 2 Disclaimer 3 Installation 4 How to Use 4.1 LibreJS in action 4.2 Script Blacklist/whitelist 4.3 Complaint Feature 4.4 Options 5 JavaScript Detection 6 Free Licenses Detection 7 Setting Your JavaScript Free 7.1 License tags 7.2 Undetected Free Licenses 7.3 Known limitations 8 LibreJS Development Notes 8.1 Dependencies 8.2 Building 8.3 Debugging 8.4 Testing 8.5 Headless testing 8.6 Headless compliance check 8.7 Adding new whitelisted libraries 8.8 Releasing a new version Appendix A Installation Requirements A.1 Mozilla Browser Appendix B LibreJS Internals Appendix C GNU Free Documentation License LibreJS ******* This manual is for GNU LibreJS (version 7.21, 17 September 2023). 1 Overview ********** GNU LibreJS --an add-on for GNU IceCat and Mozilla Firefox-- detects and blocks nonfree nontrivial JavaScript while allowing its execution on pages containing code that is either trivial and/or free. Many websites run nontrivial JavaScript on your computer. Some use it for complex tasks; many use it gratuitously for minor jobs that could be done easily with plain HTML. Sometimes this JavaScript code is malicious. Either way, the JavaScript code is often nonfree. For explanation of the issue, see "The JavaScript Trap"(). If you care about freedom in your computing, and don't wish to let all and sundry make you run nonfree programs, now you can prevent it by using LibreJS. 2 Disclaimer ************ • LibreJS is not a security tool. Its goal is to detect nonfree nontrivial JavaScript, and it currently does not detect whether free or trivial code is malicious or not. Other free Mozilla extensions and add-ons may be available for this purpose. • LibreJS is always a work in progress. If you find a bug, please report it to . 3 Installation ************** You can install LibreJS directly using a generated ‘librejs.xpi’ file, or by building it from source (*Note LibreJS Development Notes::). You can also download it from or , but due to Mozilla's review process the download isn't always up to date. 4 How to Use ************ 4.1 LibreJS in action ===================== After installing the add-on, you will see the LibreJS widget in the add-on bar at the top right of the browser window. After loading a page, left-click on the widget to view the deactivated JavaScript code from the page (both on page and external) and, if applicable, the scripts that were accepted. 4.2 Script Blacklist/whitelist ============================== Scripts may be blacklisted or whitelisted through the pop-up menu box. Whitelisted scripts will always be accepted and blacklisted scripts will always get rejected. It is important to note that this feature recognizes which scripts are blacklisted and whitelisted based on hash. This means that even a slight difference in a script's code will cause it to be recognized as a separate script. Sometimes, JavaScript will be dynamically generated so that it is different every time a website is loaded. These types of scripts cannot be whitelisted or blacklisted since they cannot be recognized. LibreJS has a default whitelist of scripts that are known to be free but may not declare their license in a format that LibreJS can understand. 4.3 Complaint Feature ===================== It is very important to complain when a site has nonfree JavaScript code, especially if it won't work without that code. LibreJS makes it easy to complain by heuristically finding where to send the complaint. When nonfree/nontrivial code is detected in a page, LibreJS attempts to find a relevant contact link or email for the website you are visiting. In order to do so, it will attempt to visit a few links from the current page (for instance, a link labeled "contact" on the same domain as the current page, ...) LibreJS detects contact pages, email addresses that are likely to be owned by the maintainer of the site, Twitter and identi.ca links, and phone numbers. When you complain to the website for their nonfree nontrivial JavaScript, provide them with the link to the JavaScript Trap essay so that they can get more information on what the issue is and how they can solve it on their own site. LibreJS includes a default subject line and body for the complaint email, with a link to the JavaScript Trap essay. This can be configured in the LibreJS add-on preferences in your web browser. 4.4 Options =========== You can manage LibreJS's preferences either from the extension's entry in your browser's Add-ons Manager page (‘about:addons’) or by clicking the LibreJS toolbar icon and then the "Settings..." button on the top right of the popup. This will open a panel containing a whitelist/blacklist manager and a section to configure your complaints messages to site owners. “Whitelist/Blacklist” LibreJS lets you whitelist or blacklist domain names and subdomains, to bypass the regular JavaScript checks. This might be useful, for example, if you are running your own code in a local web server, or if you don't want to waste computing resources on script origins you already know you can't trust. librejs provides a lists manager UI to handle both the lists on the top of its Options panel. “Complaint email subject” Configure the default subject used in complaint emails. “Complaint email body” Configure the default body used in complaint emails. 5 JavaScript Detection ********************** LibreJS considers a very strict subset of JavaScript to be acceptable for use in non-free scripts. This is meant to maximimize compatibility with websites that haven't tried to be LibreJS compatible. We consider modification of the document non-trivial. There isn't much that javascript could do that we would consider trivial, for anything else a free software license would be required. The criterion is as follows: For each function definition: • It must call only primitives. • The number of conditionals and loops must be at most 3. • It does not declare an array more than 50 elements long. • It must not call itself For the rest of the script, outside of function definitions: • It must call only primitives and functions defined above in the page. • The number of conditionals and loops must be at most 3. "function" means anything executable that gets a name, including methods. Allowed primitives exclude: • eval() • ajax • calling methods with the square bracket notation • altering the dom • most other items found as methods of the '.window' object. 6 Free Licenses Detection ************************* The machine readable format for license declarations that LibreJS uses has changed in the most recent version. This was necessary in order to not break the asynchronous JS loading model that browsers use. Scripts are now evaluated independent of eachother and strictly as they arrive. 7 Setting Your JavaScript Free ****************************** The first step is releasing your JavaScript under a free license. If you are already using a free library, or you're not using any third-party libraries, it might only take a few minutes. On your website, take a look at your HTML source. You can identify distinct pieces of JavaScript that might be free and some other that are nonfree. This might be the case with an analytics tracker, social media widgets, and code that runs ads. Removing these pieces of code from your site is required to have the rest accepted as free. There are often alternatives to nonfree libraries or to third-party services: • If you have used nonfree third-party code as the base to write your own code, try to find a free alternative. • If you're using a third-party service such as an analytics service, replace it with a free alternative like Matomo. • If you can't find free JavaScript that has already been developed, write it yourself! Who knows, your own solution might be the start of a brilliant project! 7.1 License tags ================ LibreJS will allow non-trivial scripts to run as long as they use a free license. In order for the license of a script to be recognized by LibreJS, it must be declared using a machine-readable license format. This format is the same for both remote in-line scripts. "// @license [magnet link] [identifier]" [Script here] "// @license-end" "Identifier" is a name of a license from the following list and the magnet link in the ‘canonicalUrl’ field is that license's exact corresponding magnet link. The following json object which can be found in ‘./common/license_definitions.json’ file in the LibreJS code shows all the licensees recognised by LibreJS. { "AGPL-3.0": { "licenseName": "GNU AFFERO GENERAL PUBLIC LICENSE version 3", "identifier": "AGPL-3.0", "canonicalUrl": [ "http://www.gnu.org/licenses/agpl-3.0.html", "magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt" ], "licenseFragments": [ { "text": " is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.", "type": "short" } ] }, "Apache-2.0": { "licenseName": "Apache License, Version 2.0", "identifier": "Apache-2.0", "canonicalUrl": [ "http://www.apache.org/licenses/LICENSE-2.0", "magnet:?xt=urn:btih:8e4f440f4c65981c5bf93c76d35135ba5064d8b7&dn=apache-2.0.txt" ], "licenseFragments": [ { "text": "Licensed under the Apache License, Version 2.0 (the \"License\"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0", "type": "short" } ] }, "Artistic-2.0": { "licenseName": "Artistic License 2.0", "identifier": "Artistic-2.0", "canonicalUrl": [ "http://www.perlfoundation.org/artistic_license_2_0", "magnet:?xt=urn:btih:54fd2283f9dbdf29466d2df1a98bf8f65cafe314&dn=artistic-2.0.txt" ], "licenseFragments": [] }, "BSD-2-Clause": { "licenseName": "BSD 2-Clause License", "identifier": "BSD-2-Clause", "canonicalUrl": [ "http://www.freebsd.org/copyright/freebsd-license.html", "magnet:?xt=urn:btih:87f119ba0b429ba17a44b4bffcab33165ebdacc0&dn=freebsd.txt" ], "licenseFragments": [ { "text": "Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.", "type": "short" } ] }, "BSD-3-Clause": { "licenseName": "BSD 3-Clause License", "identifier": "BSD-3-Clause", "canonicalUrl": [ "http://opensource.org/licenses/BSD-3-Clause", "magnet:?xt=urn:btih:c80d50af7d3db9be66a4d0a86db0286e4fd33292&dn=bsd-3-clause.txt" ], "licenseFragments": [ { "text": "Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.", "type": "short" } ] }, "BSL-1.0": { "licenseName": "Boost Software License 1.0", "identifier": "BSL-1.0", "canonicalUrl": [ "http://www.boost.org/LICENSE_1_0.txt", "magnet:?xt=urn:btih:89a97c535628232f2f3888c2b7b8ffd4c078cec0&dn=Boost-1.0.txt" ], "licenseFragments": [ { "text": "Boost Software License Permission is hereby granted, free of charge, to any person or organization obtaining a copy of the software and accompanying documentation covered by this license (the \"Software\") to use, reproduce, display, distribute, execute, and transmit the Software, and to prepare derivative works of the Software, and to permit third-parties to whom the Software is furnished to do so, all subject to the following", "type": "short" } ] }, "CC-BY-1.0": { "licenseName": "Creative Commons Attribution 1.0 Generic", "identifier": "CC-BY-1.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by/1.0/" ], "licenseFragments": [] }, "CC-BY-2.0": { "licenseName": "Creative Commons Attribution 2.0 Generic", "identifier": "CC-BY-2.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by/2.0/" ], "licenseFragments": [] }, "CC-BY-2.5": { "licenseName": "Creative Commons Attribution 2.5 Generic", "identifier": "CC-BY-2.5", "canonicalUrl": [ "https://creativecommons.org/licenses/by/2.5/" ], "licenseFragments": [] }, "CC-BY-3.0": { "licenseName": "Creative Commons Attribution 3.0 Unported", "identifier": "CC-BY-3.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by/3.0/" ], "licenseFragments": [] }, "CC-BY-4.0": { "licenseName": "Creative Commons Attribution 4.0 International", "identifier": "CC-BY-4.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by/4.0/" ], "licenseFragments": [] }, "CC-BY-SA-1.0": { "licenseName": "Creative Commons Attribution-ShareAlike 1.0 Generic", "identifier": "CC-BY-SA-1.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by-sa/1.0/" ], "licenseFragments": [] }, "CC-BY-SA-2.0": { "licenseName": "Creative Commons Attribution-ShareAlike 2.0 Generic", "identifier": "CC-BY-SA-2.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by-sa/2.0/" ], "licenseFragments": [] }, "CC-BY-SA-2.5": { "licenseName": "Creative Commons Attribution-ShareAlike 2.5 Generic", "identifier": "CC-BY-SA-2.5", "canonicalUrl": [ "https://creativecommons.org/licenses/by-sa/2.5/" ], "licenseFragments": [] }, "CC-BY-SA-3.0": { "licenseName": "Creative Commons Attribution-ShareAlike 3.0 Unported", "identifier": "CC-BY-SA-3.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by-sa/3.0/" ], "licenseFragments": [] }, "CC-BY-SA-4.0": { "licenseName": "Creative Commons Attribution-ShareAlike 4.0 International", "identifier": "CC-BY-SA-4.0", "canonicalUrl": [ "https://creativecommons.org/licenses/by-sa/4.0/" ], "licenseFragments": [] }, "CC0-1.0": { "licenseName": "Creative Commons CC0 1.0 Universal", "identifier": "CC0-1.0", "canonicalUrl": [ "http://creativecommons.org/publicdomain/zero/1.0/legalcode", "magnet:?xt=urn:btih:90dc5c0be029de84e523b9b3922520e79e0e6f08&dn=cc0.txt" ], "licenseFragments": [] }, "CECILL-2.0": { "licenseName": "CeCILL Free Software License Agreement v2.0", "identifier": "CECILL-2.0", "canonicalUrl": [ "https://www.cecill.info/licences/Licence_CeCILL_V2-en.txt", "magnet:?xt=urn:btih:dda0473d240d7febeac8fa265da27286ead0b1ce&dn=cecill-2.0.txt" ], "licenseFragments": [] }, "CPAL-1.0": { "licenseName": "Common Public Attribution License Version 1.0 (CPAL)", "identifier": "CPAL-1.0", "canonicalUrl": [ "http://opensource.org/licenses/cpal_1.0", "magnet:?xt=urn:btih:84143bc45939fc8fa42921d619a95462c2031c5c&dn=cpal-1.0.txt" ], "licenseFragments": [ { "text": "The contents of this file are subject to the Common Public Attribution License Version 1.0", "type": "short" }, { "text": "The term \"External Deployment\" means the use, distribution, or communication of the Original Code or Modifications in any way such that the Original Code or Modifications may be used by anyone other than You, whether those works are distributed or communicated to those persons or made available as an application intended for use over a network. As an express condition for the grants of license hereunder, You must treat any External Deployment by You of the Original Code or Modifications as a distribution under section 3.1 and make Source Code available under Section 3.2.", "type": "short" } ] }, "EPL-1.0": { "licenseName": "Eclipse Public License Version 1.0", "identifier": "EPL-1.0", "canonicalUrl": [ "http://www.eclipse.org/legal/epl-v10.html", "magnet:?xt=urn:btih:4c6a2ad0018cd461e9b0fc44e1b340d2c1828b22&dn=epl-1.0.txt" ], "licenseFragments": [ { "text": "THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE PUBLIC LICENSE (\"AGREEMENT\"). ANY USE, REPRODUCTION OR DISTRIBUTION OF THE PROGRAM CONSTITUTES RECIPIENT'S ACCEPTANCE OF THIS AGREEMENT.", "type": "short" } ] }, "Expat": { "licenseName": "Expat License (sometimes called MIT Licensed)", "identifier": "Expat", "canonicalUrl": [ "http://www.jclark.com/xml/copying.txt", "magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&dn=expat.txt" ], "licenseFragments": [ { "text": "Copyright Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the \"Software\"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.", "type": "short" } ] }, "FreeBSD": { "licenseName": "FreeBSD License", "identifier": "FreeBSD", "canonicalUrl": [ "http://www.freebsd.org/copyright/freebsd-license.html", "magnet:?xt=urn:btih:87f119ba0b429ba17a44b4bffcab33165ebdacc0&dn=freebsd.txt" ], "licenseFragments": [ { "text": "Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:\n\nRedistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.\n\nRedistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.", "type": "short" } ] }, "GNU-All-Permissive": { "licenseName": "GNU All-Permissive License", "identifier": "GNU-All-Permissive", "canonicalUrl": [], "licenseFragments": [ { "text": "Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without any warranty.", "type": "short" } ] }, "GPL-2.0": { "licenseName": "GNU General Public License (GPL) version 2", "identifier": "GPL-2.0", "canonicalUrl": [ "http://www.gnu.org/licenses/gpl-2.0.html", "magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt" ], "licenseFragments": [ { "text": " is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.", "type": "short" }, { "text": "Alternatively, the contents of this file may be used under the terms of either the GNU General Public License Version 2 or later (the \"GPL\"), or the GNU Lesser General Public License Version 2.1 or later (the \"LGPL\"), in which case the provisions of the GPL or the LGPL are applicable instead of those above. If you wish to allow use of your version of this file only under the terms of either the GPL or the LGPL, and not to allow others to use your version of this file under the terms of the MPL, indicate your decision by deleting the provisions above and replace them with the notice and other provisions required by the GPL or the LGPL. If you do not delete the provisions above, a recipient may use your version of this file under the terms of any one of the MPL, the GPL or the LGPL.", "type": "short" } ] }, "GPL-3.0": { "licenseName": "GNU General Public License (GPL) version 3", "identifier": "GPL-3.0", "canonicalUrl": [ "http://www.gnu.org/licenses/gpl-3.0.html", "magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt" ], "licenseFragments": [ { "text": " is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License (GNU GPL) as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. The code is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU GPL for more details. As additional permission under GNU GPL version 3 section 7, you may distribute non-source (e.g., minimized or compacted) forms of that code without the copy of the GNU GPL normally required by section 4, provided you include this license notice and a URL through which recipients can access the Corresponding Source.", "type": "short" }, { "text": " is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.", "type": "short" } ] }, "ISC": { "licenseName": "The ISC License", "identifier": "ISC", "canonicalUrl": [ "https://www.isc.org/downloads/software-support-policy/isc-license/", "magnet:?xt=urn:btih:b8999bbaf509c08d127678643c515b9ab0836bae&dn=ISC.txt" ], "licenseFragments": [ { "text": "Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.\n\nTHE SOFTWARE IS PROVIDED \"AS IS\" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.", "type": "short" }, { "text": "Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.THE SOFTWARE IS PROVIDED \"AS IS\" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.", "type": "short" } ] }, "jQueryTools": { "licenseName": "jQuery Tools", "identifier": "jQueryTools", "canonicalUrl": [], "licenseFragments": [ { "text": "NO COPYRIGHTS OR LICENSES. DO WHAT YOU LIKE.", "type": "short" } ] }, "LGPL-2.1": { "licenseName": "GNU Lesser General Public License, version 2.1", "identifier": "LGPL-2.1", "canonicalUrl": [ "http://www.gnu.org/licenses/lgpl-2.1.html", "magnet:?xt=urn:btih:5de60da917303dbfad4f93fb1b985ced5a89eac2&dn=lgpl-2.1.txt" ], "licenseFragments": [ { "text": " is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.", "type": "short" } ] }, "LGPL-3.0": { "licenseName": "GNU Lesser General Public License, version 3", "identifier": "LGPL-3.0", "canonicalUrl": [ "http://www.gnu.org/licenses/lgpl-3.0.html", "magnet:?xt=urn:btih:0ef1b8170b3b615170ff270def6427c317705f85&dn=lgpl-3.0.txt" ], "licenseFragments": [ { "text": " is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.", "type": "short" } ] }, "MPL-2.0": { "licenseName": "Mozilla Public License Version 2.0", "identifier": "MPL-2.0", "canonicalUrl": [ "http://www.mozilla.org/MPL/2.0", "magnet:?xt=urn:btih:3877d6d54b3accd4bc32f8a48bf32ebc0901502a&dn=mpl-2.0.txt" ], "licenseFragments": [ { "text": "This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.", "type": "short" } ] }, "PublicDomain": { "licenseName": "Public Domain", "identifier": "PublicDomain", "canonicalUrl": [ "magnet:?xt=urn:btih:e95b018ef3580986a04669f1b5879592219e2a7a&dn=public-domain.txt" ], "licenseFragments": [] }, "Unlicense": { "licenseName": "Unlicense", "identifier": "Unlicense", "canonicalUrl": [ "http://unlicense.org/UNLICENSE", "magnet:?xt=urn:btih:5ac446d35272cc2e4e85e4325b146d0b7ca8f50c&dn=unlicense.txt" ], "licenseFragments": [ { "text": "This is free and unencumbered software released into the public domain.", "type": "short" } ] }, "UPL": { "licenseName": "Universal Permissive License", "identifier": "UPL-1.0", "canonicalUrl": [ "https://oss.oracle.com/licenses/upl/", "magnet:?xt=urn:btih:478974f4d41c3fa84c4befba25f283527fad107d&dn=upl-1.0.txt" ], "licenseFragments": [ { "text": "The Universal Permissive License (UPL), Version 1.0", "type": "short" } ] }, "WTFPL": { "licenseName": "Do What The F*ck You Want To Public License (WTFPL)", "identifier": "WTFPL", "canonicalUrl": [ "http://www.wtfpl.net/txt/copying/", "magnet:?xt=urn:btih:723febf9f6185544f57f0660a41489c7d6b4931b&dn=wtfpl.txt" ], "licenseFragments": [ { "text": "DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE", "type": "short" }, { "text": "0. You just DO WHAT THE FUCK YOU WANT TO.", "type": "short" } ] }, "X11": { "licenseName": "X11 License", "identifier": "X11", "canonicalUrl": [ "magnet:?xt=urn:btih:5305d91886084f776adcf57509a648432709a7c7&dn=x11.txt" ], "licenseFragments": [ { "text": "Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the \"Software\"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.", "type": "short" } ] }, "XFree86-1.1": { "licenseName": "XFree86 1.1 License", "identifier": "XFree86-1.1", "canonicalUrl": [ "http://www.xfree86.org/3.3.6/COPYRIGHT2.html#3", "http://www.xfree86.org/current/LICENSE4.html", "magnet:?xt=urn:btih:12f2ec9e8de2a3b0002a33d518d6010cc8ab2ae9&dn=xfree86.txt" ], "licenseFragments": [ { "text": "All rights reserved.\nPermission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the \"Software\"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:\n1. Redistributions of source code must retain the above copyright notice, this list of conditions, and the following disclaimer.\n2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution, and in the same place and form as other copyright, license and disclaimer information.\n3. The end-user documentation included with the redistribution, if any, must include the following acknowledgment: \"This product includes software developed by The XFree86 Project, Inc (http://www.xfree86.org/) and its contributors\", in the same place and form as other third-party acknowledgments. Alternately, this acknowledgment may appear in the software itself, in the same form and location as other such third-party acknowledgments.4. Except as contained in this notice, the name of The XFree86 Project, Inc shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from The XFree86 Project, Inc.", "type": "short" } ] }, "Zlib": { "licenseName": "zlib License", "canonicalUrl": [ "https://www.zlib.net/zlib_license.html", "https://spdx.org/licenses/Zlib.txt", "magnet:?xt=urn:btih:922bd98043fa3daf4f9417e3e8fec8406b1961a3&dn=zlib.txt" ], "identifier": "Zlib", "licenseFragments": [] } } 7.2 Undetected Free Licenses ============================ If you are using a free license that isn't detected by LibreJS and isn't listed in the previous section, please send a message to regarding this license, where code released under this license can be found, and where to find the license text and information. Many free licenses are listed in this page: 7.3 Known limitations ===================== Service workers may cause false positives and false negatives, and there are multiple ways to disable them. The cleanest way is by setting ‘dom.serviceWorkers.enabled’ to ‘false’ in the ‘about:config’ page of your browser. 8 LibreJS Development Notes *************************** 8.1 Dependencies ================ LibreJS 7.21 depends on a number of Node.js-based libraries that can be installed using the ‘npm’ utility: $ npm install acorn@"<=8.7.1" jssha browserify $ export PATH=$PATH:./node_modules/.bin 8.2 Building ============ To build the extension run: $ browserify main_background.js -o bundle.js To build the extension plus create a .xpi package run: $ ./build.sh To build the extension including the automated test suite (see TEST below) run: $ ./build.sh -t or $ ./build.sh --test Note: this ‘build.sh’ script relies on no new source files being created. 8.3 Debugging ============= To debug LibreJS, visit the special URL ‘about:debugging’. Click on 'Enable add-on debugging' then 'Load Temporary Add-on'. Navigate to LibreJS's unpacked source directory and select ‘manifest.json’. Lines 39 and 40 in ‘main_background.js’ assign two variables controlling the verbosity of ‘dbg_print()’ statements. Make sure these are set to false before building a release. 8.4 Testing =========== An automated test suite runs automatically in its own tab whenever the extension is loaded as a "Temporary add-on" from ‘about:debugging’. Otherwise (if included in the xpi) it can be launched from the UI by clicking the "Automated self test..." button. 8.5 Headless testing ==================== To launch the test suite from the command line, ensure the xpi package has been built with automated test suite. Then install selenium-webdriver and geckodriver, and ensure the latter is in $PATH: $ npm install selenium-webdriver geckodriver $ export PATH=$PATH:./node_modules/.bin Now you can invoke the test with $ node ./utilities/test.js which will print out a summary of test results. Optionally you can also test with a chosen seed $ node ./utilities/test.js 12345 8.6 Headless compliance check ============================= To check whether a webpage is LibreJS-compliant from the command line, ensure that the xpi package has been built WITHOUT the automated test suite. Then install selenium-webdriver and geckodriver, and ensure the latter is in $PATH: $ npm install selenium-webdriver $ npm install geckodriver $ export PATH=$PATH:./node_modules/.bin Now you can check a webpage for compliance with $ node ./utilities/compliance.js It will open the url in a headless browser, save a screenshot, and output the compliance check result. For example, to check the compliance of the FSF homepage, do $ node ./utilities/compliance.js https://fsf.org 8.7 Adding new whitelisted libraries ==================================== The script index.js in ‘./utilities/hash_script’ generates the default whitelist. Run it with the following command: ‘node index.js > output’ Then, just copy the contents of the file "output" to the appropriate place in main_background.js. 8.8 Releasing a new version =========================== 1. Run some tests and make sure they all pass. 2. Make sure debug statements are set to false on lines 39/40 in ‘main_background.js’. 3. Update the version number in manifest.json. 4. Add user-visible changes to ‘NEWS’. 5. Update the version number in ‘docs/version.texi’. 6. Commit and tag the release, and push to Savannah. 7. Run build.sh in a clean repo and upload the generated ‘librejs.xpi’ to Mozilla. 8. Fix any validation warnings or errors during the upload in the previous step, test, re-tag the release, re-push to Savannah, and re-upload to Mozilla. 9. Generate docs from ‘docs/’ using gnulib gendocs.sh script (), and commit the docs to the website cvs repo under the ‘manual/’ directory. This will update the docs at . 10. From this step onwards it is required that Mozilla has approved the new version. Download the signed xpi from Mozilla website (). 11. Follow the steps in Information for GNU Maintainer to upload the source tar ball (downloadable from cgit) and the signed xpi to the GNU FTP server. 12. Update the download links on the LibreJS webpage () to point to the new release. 13. Announce to info-gnu, help-librejs, bug-librejs mailing lists, and the Savannah project News section. 14. (Optional) Update projects that uses LibreJS like gnuzilla and abrowser. Appendix A Installation Requirements ************************************ A.1 Mozilla Browser =================== You will need one of the many flavors of the Mozilla browser to use LibreJS. It can be installed on the following: GNU IceCat, Mozilla Firefox, Trisquel Abrowser, Debian Iceweasel. LibreJS works on these browsers starting from version 60. We recommend that you use the latest version of your Mozilla browser. LibreJS has been tested on a GNU/Linux distribution, but it is compatible any operating system as long as you're using a compatible Mozilla browser. Appendix B LibreJS Internals **************************** LibreJS intercepts HTTP responses and rewrites their contents after analyzing JavaScript within them. It does not remove script nodes and attributes from the page, but instead "deactivates" them by replacing their content with a commented notice. LibreJS detects the most common cases using the HTTP response method described above, but in less common edge cases, or when running code locally, LibreJS cannot detect JavaScript during the response stage. Appendix C GNU Free Documentation License ***************************************** Version 1.3, 3 November 2008 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. 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ADDENDUM: How to use this License for your documents ==================================================== To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the "with...Texts." line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.