$ git clone -n https://src.fedoraproject.org/rpms/replacer.git /var/lib/mock/f40-build-2268236-54734/root/chroot_tmpdir/scmroot/replacer
Cloning into '/var/lib/mock/f40-build-2268236-54734/root/chroot_tmpdir/scmroot/replacer'...
$ git fetch origin f0b90964c84e3b36d19e78d1517c27f1ea91fb9b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/replacer
 * [new ref]         f0b90964c84e3b36d19e78d1517c27f1ea91fb9b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f0b9096 Fix build with maven-plugin-plugin 3.9