For Shorts, YouTube is experimenting with a new "Save" button so that it's easier for Shorts viewers to get back to their favorite Shorts clips in the app, also seeing it move the "Dislike" button from the main Shorts UI.

Which could have an even bigger impact.
the right-hand function icons for the current YouTube Shorts player feature "Like" and "Dislike" icons at the top of that list; the newest iteration of Shorts also adds a "Remix" icon at the bottom of the list, among others.

But in this new test for those users, the thumbs-down icon will be cut from the mix to make room for a "Save" button instead.
YouTube explains

"To make it easier to bookmark Shorts that you love, want to return to, or want to watch later, we're experimenting with a "Save" button in the Shorts player. If you're a viewer in the test group, you'll see the 'Save' icon which you can use to save Shorts to a new or existing playlist. To make room for the Save button, we moved our Shorts player menu around. Moving the "Dislike" button to the 3-dot menu icon In this experiment, click the 3-dot icon in the top right of the Short you're watching then select 'Dislike' from the menu.

So, you will still be able to like Shorts in the main UI, but to mark that you dislike a clip, you will have to dig a little deeper.

Could affect the Shorts feedback loop, how you personalize your Shorts feed. On the other hand, the YouTube Shorts algorithm is based on many things, including watch time and engagement; really, it could probably infer your dislike of clips based on how fast you scroll past it anyway.

But it is an interesting shift, which does suggest Shorts viewers aren't actively using the dislike button nearly as much as the like. Which makes sense, but that gap must be pretty huge for YouTube to even consider taking this out of the front-and-center view.

As if that were not enough, the three dots menu on Shorts player already has "Not interested". So, you are going to have both "Dislike" and "Not Interested" buttons now? Isn't that a philosophical conundrum to be faced with now? "Did I dislike it or was I just not interested?" May change your outlook on life.

Clarification, the "Save to Playlist" option is also currently in the three dots menu, it'll just be swapped with "Dislike" for those in the test.

This is only an experiment for now, so it may not amount to much either way, but worth noting in terms of functional and behavioral trends.

YouTube says that it's rolling this experiment out "to a small number of viewers on mobile devices."