Source: https://github.com/TeamNewPipe/NewPipe/pull/9182#issuecomment-1508938841

Note: we recently discovered that YouTube system playlists exist for regular videos of channels, for livestreams, and shorts as chronological ones (the shorts one was already known) and popular ones.
They correspond basically to the results of the sort filters available on the channels streams tab on YouTube's interface

So, basically shortcuts for the lazy/incurious?

Same procedure as the one described in the 0.24.1 changelog, except that you need to change the prefix UU (all user uploads) to:

UULF for regular videos only,
UULV for livestreams only,
UUSH for shorts only,
UULP for popular regular videos,
UUPS for popular shorts,
UUPV for popular livestreams
UUMF: members only regular videos
UUMV: members only livestreams
UUMS is probably for members-only shorts, we need to found a channel making shorts restricted to channel members