$ git clone -n https://src.fedoraproject.org/rpms/gnome-user-docs.git /var/lib/mock/f42-build-59042704-6570522/root/chroot_tmpdir/scmroot/gnome-user-docs
Cloning into '/var/lib/mock/f42-build-59042704-6570522/root/chroot_tmpdir/scmroot/gnome-user-docs'...
$ git fetch origin 3c377ef63a84df381792495a6cffd983e219e392:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-user-docs
 * [new ref]         3c377ef63a84df381792495a6cffd983e219e392 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3c377ef Update to 48.1