Out of the box, µMatrix works in relax block-all/allow-exceptionally mode, meaning web sites which require 3rd-party scripts are likely to be "broken". With two clicks, µMatrix can be set to work in allow-all/block-exceptionally mode, which generally will not break web sites. See https://github.com/gorhill/httpswitchboard/wiki/How-to-use-HTTP-Switchboard:-Two-opposing-views for more details on this topic.
Regarding the myth that "Chromium-based browsers can't reliably block javascript", see: https://github.com/gorhill/httpswitchboard/wiki/Blocking-javascript-execution-reliably-in-Chromium-based-browsers. Summary: Yes, javascript can be blocked reliably in Chromium.
Regarding the myth that "Chromium-based browsers can't reliably block JavaScript", see: https://github.com/gorhill/httpswitchboard/wiki/Blocking-javascript-execution-reliably-in-Chromium-based-browsers. Summary: Yes, JavaScript can be blocked reliably in Chromium.
* See ALL the remote connections, failed or attempted, depending on whether they were blocked or allowed (you decide).
* A single-click to whitelist/blacklist one or multiple classes of requests according to the destination and type of data (a blocked request will NEVER leave your browser).
* Efficient blacklisting: cookies won't leave your browser, javascript won't execute, plugins won't play, tracking pixels won't download, etc.
* Efficient blacklisting: cookies won't leave your browser, JavaScript won't execute, plugins won't play, tracking pixels won't download, etc.
* You do not have to solely rely on just one particular curated blacklist (arguably with many missing entries) outside which nothing else can be blocked: You are in full control.