In default Firefox you can access UBlock Origin in the top right in order to turn it on/off for a page, use the element picker, change settings, etc. Not only is this gone in Pulse, but it isn't listed under addons, so there's no way to access settings.
This appeared to be an issue with that instance or the installed build, cannot replicate. If anyone can replicate it, please create a new issue with instructions.
From IHave on discord: