$ git clone -n https://src.fedoraproject.org/rpms/tailscale.git /var/lib/mock/f41-build-834103-158057/root/chroot_tmpdir/scmroot/tailscale
Cloning into '/var/lib/mock/f41-build-834103-158057/root/chroot_tmpdir/scmroot/tailscale'...
$ git fetch origin 29f33560991b3356859f306a27fee9de7bf9af97:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/tailscale
 * [new ref]         29f33560991b3356859f306a27fee9de7bf9af97 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 29f3356 update to 1.70.0