$ git clone -n https://src.fedoraproject.org/rpms/mpv.git /var/lib/mock/f40-build-1804446-24879/root/chroot_tmpdir/scmroot/mpv
Cloning into '/var/lib/mock/f40-build-1804446-24879/root/chroot_tmpdir/scmroot/mpv'...
$ git fetch origin 5fc92105017f0329aa0d7b98d9f5c98c4f952cea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mpv
 * [new ref]         5fc92105017f0329aa0d7b98d9f5c98c4f952cea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5fc9210 Rebuild against fixed mujs to address dynamic linking issues