Earlier quoted context omitted.
uMatrix is uBlock Origin (uBO) with 2 differences: 1) No cosmetic filtering. 2) A more powerful interface, as _underfl0w_ describes at https://news.ycombinator.com/item?id=25302405 The key thing which that comment does not mention is that the interface enables a whitelist approach — block everything (read: as much as you want) by default and selectively allow certain types of content from certain sites. This is impor…
Actually, you _can_ configure uBO to block third-party content by default (by turning on advanced user mode); however, it's not as good as uMatrix as there is no split of request type (script versus image, etc.) as well as no UI to manage subdomains. You'll have to do that last part by editing the text configuration manually.
UI screenshot: https://i.imgur.com/o0UsSdP.png