$ git clone -n https://src.fedoraproject.org/rpms/mpv.git /var/lib/mock/f41-build-856952-167848/root/chroot_tmpdir/scmroot/mpv
Cloning into '/var/lib/mock/f41-build-856952-167848/root/chroot_tmpdir/scmroot/mpv'...
$ git fetch origin 9e36faf686e1285204b1b75a07da03ddff283a84:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mpv
 * [new ref]         9e36faf686e1285204b1b75a07da03ddff283a84 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9e36faf Update mpv to 0.39.0