uBO (uBlock Origin) is a popular open source ad blocker. There is a change coming to the way Google Chrome and some other browsers host extensions called manifest v3, which for (stated) security and privacy purposes limits a lot of the functionality that makes ad blockers work the way they do. There are workarounds but they are suboptimal. This has been an ongoing fight for years and there are plenty of accusations that Google is doing this because they want to cripple ad blockers since they make so much money from advertising. Firefox has explicitly stated they will not force these changes on extension developers, and thus a lot of people have been threatening to move to Firefox whenever Google finally makes this change for real.

Maybe it’s a telling sign of the new wave of HN users, but I’m genuinely surprised to read that you don’t know what uBlock is..

I'm happy youngsters still use this ol' forum

It’s good that we are still getting Youngbloods who see the superiority of text in communications rather than one sided talking head videos.

"uBO" is an abbreviation of "uBlock Origin".