blocking ads without third-party extensions.

I've tried the Android version of Opera and it wasn't bad. It had it's own VPN (server) and there's also "Opera Mini" for android which is a mini browser that's bare bones (lightweight) like Firefox Focus (Android) is. However since I use Edge for Android and Samsung Browser secondary I didn't keep Opera. Only so many browsers I need especially on Android.  I haven't tried on Windows in years since they went Chromium engine. 

Only thing about adding a browsers own ad blocker is...you get their ad blocker whether their own version or they partner with a third party. With extensions you can pick your ad blocker whether it's Ublock or ABP or something else.  I had Ublock and found it stopped working for me on various of websites so I switched to Adblock Plus and it works fine. I don't always use it too as some websites break especially news sites telling you to turn it off. So I mostly defaulted ABP to off expect for a few websites I know that are ad filled upon launching. If websites start locking said ad blocker you can try delete and another one instead of being tied into the single one built into the web browser. 

That's the only down side to a built in ad blocker. I guess it would have to have default options settable to on and off options or to be able to delete, and still allow users to use their own third party ad blocker if they choose. VPN would be a pretty cool concept especially tied in or secondary option tied into InPrivate. I liked the VPN options on Opera Android.