$ git clone -n https://src.fedoraproject.org/rpms/rubygem-git.git /var/lib/mock/f40-build-2639134-66340/root/chroot_tmpdir/scmroot/rubygem-git
Cloning into '/var/lib/mock/f40-build-2639134-66340/root/chroot_tmpdir/scmroot/rubygem-git'...
$ git fetch origin c3daa6046a47e2823a943e108303b46a42eef2c0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-git
 * [new ref]         c3daa6046a47e2823a943e108303b46a42eef2c0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c3daa60 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild