そうなりますね

> This extension is Chromium-only. For a maintained Firefox fork, see nos2x-fox.

fiatjaf/nos2x: nostr signer extension

https://github.com/fiatjaf/nos2x#nostr-signer-extension

> The Firefox branch is basically abandoned since I stopped using Firefox myself,

Firefox vs Chrome code branches, which one? · Issue #18 · fiatjaf/nos2x

https://github.com/fiatjaf/nos2x/issues/18#issuecomment-1367640331