At this time, the Windscribe browser extension does not use R.O.B.E.R.T. (our server-side ad and tracker blocker), as R.O.B.E.R.T blocking is done at the DNS level.
The current Windscribe browser extension ad and tracker blocking is based on uBlock and other custom block lists which is good because it will actually clear out the ads from web pages you visit as it works within your browser rather than on our servers. The domains are blocked before the DNS queries even go out to a DNS server as the uBlock engine knows about these domains locally.
If you are using the Windscribe desktop app and browser extension, blocking in browser will be done via the browser extension (not R.O.B.E.R.T) and will override the R.O.B.E.R.T. settings (as long as the ad and tracker blockers are enabled in the Windscribe extension Preferences).
We plan to implement R.O.B.E.R.T into the extension soon though, so the desktop, mobile and browser clients will all use a unified R.O.B.E.R.T. configuration.