$ git clone -n https://src.fedoraproject.org/rpms/python3.8.git /var/lib/mock/f39-build-1616925-38650/root/chroot_tmpdir/scmroot/python3.8
Cloning into '/var/lib/mock/f39-build-1616925-38650/root/chroot_tmpdir/scmroot/python3.8'...
$ git fetch origin e57fae03213f0461f3989d69560e6a34e9296a59:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python3.8
 * [new ref]         e57fae03213f0461f3989d69560e6a34e9296a59 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e57fae0 Update to 3.8.18