$ git clone -n https://src.fedoraproject.org/rpms/kbrickbuster.git /var/lib/mock/f40-build-2253308-54210/root/chroot_tmpdir/scmroot/kbrickbuster
Cloning into '/var/lib/mock/f40-build-2253308-54210/root/chroot_tmpdir/scmroot/kbrickbuster'...
$ git fetch origin 3a2c03c241ea76e9fa0a67a9e7c2862de24ec985:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kbrickbuster
 * [new ref]         3a2c03c241ea76e9fa0a67a9e7c2862de24ec985 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a2c03c new version