$ git clone -n https://src.fedoraproject.org/rpms/glibc.git /var/lib/mock/f40-build-730423-103231/root/chroot_tmpdir/scmroot/glibc
Cloning into '/var/lib/mock/f40-build-730423-103231/root/chroot_tmpdir/scmroot/glibc'...
$ git fetch origin c0b92fe18e67d5152db95240b2780c6f77b991b3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/glibc
 * [new ref]         c0b92fe18e67d5152db95240b2780c6f77b991b3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c0b92fe Fix force-first handling in dlclose (#2244992)