$ git clone -n https://src.fedoraproject.org/rpms/rust-arcstr.git /var/lib/mock/f42-build-3252987-41225/root/chroot_tmpdir/scmroot/rust-arcstr
Cloning into '/var/lib/mock/f42-build-3252987-41225/root/chroot_tmpdir/scmroot/rust-arcstr'...
$ git fetch origin 9d9610d37180ffdfefb254c59ddaf6277eb188a9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-arcstr
 * [new ref]         9d9610d37180ffdfefb254c59ddaf6277eb188a9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9d9610d Rebuilt for https://fedoraproject.org/wiki/Fedora_42_Mass_Rebuild