$ git clone -n https://src.fedoraproject.org/rpms/rust-rayon-core.git /var/lib/mock/f39-build-1519791-35821/root/chroot_tmpdir/scmroot/rust-rayon-core
Cloning into '/var/lib/mock/f39-build-1519791-35821/root/chroot_tmpdir/scmroot/rust-rayon-core'...
$ git fetch origin 6971d839540febcc6c3c083f199c45d1067edd24:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rayon-core
 * [new ref]         6971d839540febcc6c3c083f199c45d1067edd24 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6971d83 Update to version 1.12.0; Fixes RHBZ#2239946