RevisionSlider was originally a prototype gadget created by the Community Tech team in October 2015, inspired by DerHexer's revisionjumper gadget. It was designed to help editors navigate through diff pages without having to go back and forth between the diff and history pages. This saves time and page loads.
The most recent 50 edits to the page are represented on a slider, and you can move two blue handles along the slider to choose the diff that you want to see. When you hover on the slider, a tooltip pops up that shows you the timestamp, user and edit summary associated with that edit.
In this prototype, the slider only appears if both revisions are within the most recent 50 edits to the page.
One of the requests that came up in the All Our Ideas survey was to build an extension that has the same functionality as Revisionjumper.
It's a helpful (and possibly underused) gadget – it saves time and pageloads if you don't have to keep going back to the history page – but there are some potential deficiencies that we were looking at. Revisionjumper allows you to go back 10, 50, 100 and 150 revisions, and similar jumps in time. But it doesn't have fine-tuning, and there isn't a signal on the page that helps you figure out which revision you're aiming at.
When we were talking about Revisionjumper, we came up with an idea that could give people more fine-tune control. It was easy to make a quick prototype that we could show to people, which helps us find out if that's an option worth exploring as a way to respond to the request for a Revisionjumper extension.