Looks like the extensions are still available in the US: https://addons.mozilla.org/en-US/firefox/addon/censor-tracke... https://addons.mozilla.org/en-US/firefox/addon/%D0%BE%D0%B1%...

So it looks like they are still signed, but they are not available on amo in Russia. The extensions can still be installed on production Firefox builds if they are hosted elsewhere, such as:

Runet Censorship Bypass: https://files.catbox.moe/g7mww2.xpi

Censor Tracker: https://files.catbox.moe/37grym.xpi