Earlier quoted context omitted.
It is a little fiddly to set up at first, certainly. There are a few tools to make it easier though: if you're dealing with a site that uses a lot of semi-random subdomains (like googlevideo or cloudflare), it's possible to just whitelist the whole domain and get all the subdomains automatically (and then block individual subdomains if you want). It might be defeating the purpose, but you can also change the "scope"…
> sync my black/whitelists through Firefox Sync It's technically possible, although UX is terrible. Go to uMatrix settings, make sure to "enable cloud storage" option is set in the "settings" tab, then manually upload and download rules in the "my rules" tab. No automatic sync (won't be implemented[1]) and, no merges at the moment (button's broken[2]). [1] https://github.com/gorhill/uMatrix/issues/467 [2] https://git…
By design. Losing all rules because of sync snafu out of control of uMatrix is the absolute worst case. Importing/merging manually will prevent such disaster.