$ git clone -n https://src.fedoraproject.org/rpms/gnome-calculator.git /var/lib/mock/f40-build-59064682-6570730/root/chroot_tmpdir/scmroot/gnome-calculator
Cloning into '/var/lib/mock/f40-build-59064682-6570730/root/chroot_tmpdir/scmroot/gnome-calculator'...
$ git fetch origin 388568e29d62b2d0dce158aa9ab6ab6ac7e5addd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-calculator
 * [new ref]         388568e29d62b2d0dce158aa9ab6ab6ac7e5addd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 388568e Update to 46.3