Ideally it would be universal so any mobile client can sign into any desktop client. I’d start with @Vitor Pamplona, he implements all the NIPs!
People are working on dedicated native mobile signer apps as we speak. @greenart7c3 just released NIP-46 support on Amber, an Android signer. nostr:note17dlrejdnn878zllmwjajzun3wldwsxdkqht8dzw4dusarvee96vqq3e3vw @Alex Gleason and @Karnage also are working on this. I have iOS on my aspirational backlog, but I’m pretty backlogged.
Yep, this is probably a feature of Signers, not the clients themselves.