Amber let's you use Bunker login on Nostr web apps, on your phone or other devices. The relay connection is part of that. As for battery usage it is always <1% on my phone.
#asknostr any ideas why the android signer #amber needs relays? Its a signer for other apps, for what purpuse would I add relays to it? Also this persistent notification makes me think it might be a battery drainer :) https://cdn.nostrcheck.me/546b924fb57b1b3b243092465a74333f536e18bf46ec63fdbc732d6b5719729d/0ae006ba4b824394e5edc604f31e23374958a4620306d181a5e245ed61f7c745.webp
Discussion
And this relay.nsec.app handles this? Could I add my own relay here? Do you know of any good resource to learn more about how this works? :)
Yes, relay.nsec.app is the default for handling bunker/remote signing, but it can be configured to use a relay you choose. Not all relays accept the signing event types that are used for this signing method, though.
I go over both signing methods Amber uses in my full review of Amber at https://www.nostr-reviews.com.