At this time, the Windscribe browser extension does not use R.O.B.E.R.T. (our server-side blocker), as R.O.B.E.R.T blocking is done at the DNS level.
The current Windscribe browser extension, based on uBlock and other custom block lists, 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 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 ROBERT settings.
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 ROBERT configuration.