Does anyone know about the "UL0123456789w" YouTube channel playlist feature?

Hey everyone, I came across something interesting and was wondering if anyone has more info about it.

Apparently, if you add UL0123456789w as a playlist code in any YouTube video URL, like this:

https://youtu.be/NhheiPTdZCw?list=UL0123456789w

It creates a full channel playlist in chronological order.

This is different from the usual channel playlists that have codes like:

https://youtu.be/NhheiPTdZCw?list=UULFEXRv_qihRwjsV91ftx23-A

Which are annoyingly in reverse chronological order.

I am not sure how I discovered this code, it was just attached to a video I had previously bookmarked. The one I found was actually ULkzm2LPtrdJw but I tinkered with it and figured out that only the first UL and last w actually matter and the ten characters between them can be any letter or number.

Does anyone know anything about this or if it's an official feature? Any insights would be appreciated!

Thanks!