$ git clone -n https://src.fedoraproject.org/rpms/GMT.git /var/lib/mock/f40-build-2125207-50778/root/chroot_tmpdir/scmroot/GMT
Cloning into '/var/lib/mock/f40-build-2125207-50778/root/chroot_tmpdir/scmroot/GMT'...
$ git fetch origin b1c2cda94ee77743fcdd295b158e59a0642238d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/GMT
 * [new ref]         b1c2cda94ee77743fcdd295b158e59a0642238d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b1c2cda Rebuild (gdal)