How can I remove sidebar title?

[dmiric]

I used to have this hidden before and since I updated the FF to v141 I think the option is gone or I can't find it anymore.

[rumpff]

put this in your userChrome.css

#sidebar-header {
  display: none !important;
}

(follow this: https://superuser.com/a/319322 on how to access it)