$ git clone -n https://src.fedoraproject.org/rpms/rust-platforms.git /var/lib/mock/f40-build-2251017-54102/root/chroot_tmpdir/scmroot/rust-platforms
Cloning into '/var/lib/mock/f40-build-2251017-54102/root/chroot_tmpdir/scmroot/rust-platforms'...
$ git fetch origin b658b52c3da0ce77c62b4bf708227ef42485014c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-platforms
 * [new ref]         b658b52c3da0ce77c62b4bf708227ef42485014c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b658b52 Update to version 3.3.0; Fixes RHBZ#2256106