In the default display of (real or virtual) categories in Todo mode, Todo Archive mode and Todo Filtered Item mode the items are visually numbered in ascending order, starting with ‘1’ on the top item, displayed to the left of its header (date/time string). With todo items the numbers indicate each item’s priority in the list, so when you reprioritize an item with # or move it with m, these numbers make it easier to choose the item’s new priority. The numbering also lets you to see at a glance how many items there are in the list. When an item is inserted, deleted, or moved, the numbering is automatically updated. In Todo mode, the todo and done items sections in each category are separately numbered.
If you prefer not to have item numbering displayed, disable the option
todo-number-prefix; then the display of each item starts by default
simply with its header. But you can also replace the numbering with a
visually distinctive string of your choice by customizing the option
todo-prefix (the empty string by default). Another alternative is to
temporarily hide the item numbering:
Toggle between displaying item numbering and displaying the
todo-prefix string in the current Todo file (todo, archive, or
saved virtual category of filtered items). (This command also works in
buffers of filtered items that have not yet been written to a file.)
In the todo items section of each Todo mode category, the item prefix
(whether a priority number or a fixed string) of the top priority
items (determined as specified in see Filtering Items) is
displayed in a face (todo-top-priority) different from the face
of the prefix of non-top-priority items, so you see at a glance how
many items in the category are top priorities.