$ git clone -n https://src.fedoraproject.org/rpms/gnome-calculator.git /var/lib/mock/f42-build-side-1-3498047-45961/root/chroot_tmpdir/scmroot/gnome-calculator
Cloning into '/var/lib/mock/f42-build-side-1-3498047-45961/root/chroot_tmpdir/scmroot/gnome-calculator'...
$ git fetch origin 9960bfa449f3eb983a7dbcf51a350c7f0a8e9671:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-calculator
 * [new ref]         9960bfa449f3eb983a7dbcf51a350c7f0a8e9671 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9960bfa Update to 48.1