Keybase tracked keys added to GPG Keychain with false email address

I invited a friend to keybase, and when she had signed up I tracked her. Her key was added to my GPG keychain (osx) as myfriend@keybase.io. This, clearly, isn't her email address, and it means that I can't use normal GPG tools to encrypt messages to her (e.g. though the mail plugin). Is this default behaviour, and does it mean that other users see my email as myname@keybase.io? Generating a key for a nonexistant email address seems to be an odd way of going about things...

The issue names no source files, tests, or entry points. Start by reproducing Keybase tracking on macOS and inspecting the identity added to the GPG keychain; done means the reported identity behavior is explained or corrected and encryption through normal GPG tools works as expected.

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