Nixos-shell: gpg-connect-agent on root login

When I start up a VM via nixos-shell, I get errors from gpg-connect-agent on root autologin, even though I have not enabled gpg-agent in my VM config.

gpg-connect-agent: no running gpg-agent - starting '/nix/store/wwfj0b0mbl9lcnd79xp3r9jxy6ylv2k8-gnupg-2.4.5/bin/gpg-agent'
gpg-connect-agent: waiting for lock (held by 829003) ...

And it keeps printing the waiting for lock message about once a second until I interrupt it (as in ^C). How can I figure out what is starting this?