We are planning to deploy the RevisionSlider on de-wiki and most probably also a left-to-right language wikipedia (arabic and/or hebrew) first to gather feedback both from a left-to-right and a right-to-left language wiki. If that goes well, we plan to enable the RevisionSlider as a beta feature on all wiki projects. Based on the feedback we get, we will decide by December the latest if this is going to be a real feature or undeployed.
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