Just ten years ago, in 2013, Steam on Linux used a right-pointing cursor. Can you guess why?
The right-pointing cursor is called "arrow". The normal left-pointing cursor is, obviously, called "left_ptr".
There is also a "right_ptr", which is different from "arrow".
The modern Xcursor theme is a semi-random collection of links to a few basic cursor shapes.
For example, to show a cursor with a question mark, GNOME might refer to "help", but KDE might refer to "whats_this". This should be the same cursor, but since there's no coordination and everything is file-based, you end up with a lot of symbolic links.
For some reason, there are a lot of hashes of fuck knows what mixed in there as well.
This is not documented anywhere, by the way.