@Johanna Strodt (WMDE) Not him, but I can chime in here. I am commenting as more of a user than a commenter and editor, so apologies if I am missing something RE wikipedia feedback customs. First, I want to just say that wow, this feature is totally amazing and extremely helpful. Thank you so much to you and your team for making it, and to the german wikipedia-ers for requesting it. I do agree with @Jazzy Prinker though. In fact, I only realized the yellow and blue sliders did anything at all until I came here and saw that post. After seeing this post, I went back and found the tutorial, and saw that there was some info listed about it that I had skipped over. It seems like that one is on me, I should have just read the instructions more carefully, since that feature was in fact clearly explained. But, since both he and I ran into that issue, maybe something about the wording or the explanation could be changed to make it a bit more apparent how it all works. For example, instead of a small call-out box explaining how the revision history button works, you might instead point to the actual sliders on the page that the user is on, and point them to the actual ones that exist--something like: these sliders here, see these? they let you do such and such.
Additionally, regarding the tutorial: I wish there were more info about this thing on the tutorial itself. Even if that's just a link. Something like: To learn more about the revision slider, and how to use it, click here (then a link to some more in depth tutorial). I am glad I came to the feedback page. I learned much more about everything here. And, I did ultimately find all the info I needed, but only after arriving here. I imagine most users won't go through the hassle of all that and might just get lost or confused and give up.
Then, one final comment as long as I am posting this. This comment is in fact the reason why I came to the feedback page in the first place. It might not belong here in this section, feel free to move this around or edit it or whatever if it's better in a different or separate spot. The biggest issue to me is how to access the revision slider! It's kind of buried. This is the way I accessed it as a wikipedia user: I went to a wikipedia page on a political issue and that I expected would get edits all the time for political reasons in addition to the usual reasons. I read the main page, then wanted to check some of the revisions that got made earlier in time. I clicked on one of the older revisions sort of at random to see how things looked at some different time. Then, AFTER clicking that, that's when the "view revisions interactively" box and button showed up on the screen for the first time. So getting to it required me to click three separate times and the third click I very rarely do (i.e., the one where I actually click to see one of the earlier revisions). I think that is probably a pretty common way to use wikipedia, and I image there are many other users in the same boat.
From my own perspective, I would have loved using that slider from the very beginning--why bother jumping through all the hassle of looking at the contribution page (which is just a jumble and not easy to understand at all) when I can instead jump directly to the interactive revision page. Just for the purposes of providing a specific recommendation instead of just criticism, I think something that might be helpful to address this issue would be to include a link or to more clearly provide information about the interactive revision page on the wikipedia page I'm on, and how to access it.
Thanks again! This is one of the best additions to wikipedia in a very long time! I love it!