The RevisionSlider is a stable beta feature on 5 wikis so far, with more than a 1000 users. It should now become a beta feature on all wikis, so the community can try it out to decide if this should become a permanent feature.
The RevisionSlider should become a beta feature at the end of August (likely week 35).
As per the deployment plan discussed in T138943: Deploy Revision Slider on test Wikipedia , we want to have a decision whether or not to enable it as a default by December.
The revision slider is a feature that adds a visualization of all revisions to the compare screen. Revisions are represented as bars on a line and can be selected using two pointers. The revision slider was originally prototyped by the WMF Community Tech team and then handed over to the WMDE TCB team, as it is also a solution to fulfill a wish of the German Community Wishlist: https://de.wikipedia.org/wiki/Wikipedia:Umfragen/Technische_W%C3%BCnsche_2015/Artikel#Anzeige_aller_Bearbeitungskommentare_im_Diff