Understandable. If I was implementing a Nostr app at this stage, I would probably include a signer app built-in for a mobile and desktop app (not for a web app) as the default. If there is an Andriod distro with Nostr support to replace Google Play Services, then it could be assumed available and no longer needed, but we're not there. A Nostr "web browser" could also be something that could have built-in Nostr support (no need for additional extensions) that could include a signer and other base features for Nostr apps.