When using a signer in the app, is it a concept that is dependent on a specific app, or does it work in a way where any signer that meets a certain interface on the same phone can automatically handle requests?

Given that using #amethyst specifies "logging in with 'Amber'" and mentions a specific app name, it seems like it leans towards the former. However, if it were the latter approach, it would be more convenient. For example, browser signers like nos2x or Alby work seamlessly with any compatible signer.

There might be technical challenges involved, though.