Check: https://docs.soapbox.pub/ditto/signing

Ditto is a legacy REST API server similar to Mastodon. In this design, NIP-46 is the most viable way to sign events.

Soapbox (the frontend) has been updated to include a full NIP-46 signer implementation. When you use it, it uses NIP-07 over NIP-46!

This design is actually insane. But it also makes the most sense. The frontend (Soapbox) is not a "Nostr client" at all. It is actually a Mastodon client. The Ditto server is a hybrid Nostr client and relay, and it is actually the Ditto server which publishes your event to other relays.