It comes with ublock installed by default, it also defaults to having certain features enabled by default like clearing cookies on browser exit, letter boxing enabled, and webgl disabled. This may or may not hamper your usage of the browser, but you can enable/disable this stuff via the settings.
You can also go to the Firefox extension marketplace and install extensions natively.
picsou@jlai.lu 3 weeks ago
It is the same browser so yes to both of your questions