The HangingIndent command was created recently and it is used in the Writer sidebar, but I can find no documentation about it:
Setting to NEW...
I am willing to add something to help, but cannot find any relevant information from the source code or from experimenting with the command.
Here is patch: https://gerrit.libreoffice.org/c/core/+/35930/
No indication of tdf bug #.
Not mentioned in release notes.
Could not see a "tooltip" in source code.
Does not seem to appear in Sidebar at present (22.214.171.124, 126.96.36.199), and does not seem to be included in any toolbar.
After adding to toolbar, could not get any noticeable change from clicking on icon.
There are help pages about making hanging indents:
but they do not address this command.
1. Set First line Indent greater than zero.
2. click on Hanging Indent icon in toolbar.
Result: Can exchange (back and forth) values for "left indent" and "first line indent".
Purpose? Useful for?
Seth Chaiklin committed a patch related to this issue.
It has been pushed to "master":
tdf#113804 add explanation about Hanging Indent .uno
When the online help is updated from master (in a few days), then it should be possible to see help for "Hanging Indent" at: https://help.libreoffice.org/7.1/en-US/text/swriter/guide/indenting.html
Closing as FIXED