$ git clone -n https://src.fedoraproject.org/rpms/rust-alloc-stdlib.git /var/lib/mock/f38-build-side-43-rust-devel-1397137-31052/root/chroot_tmpdir/scmroot/rust-alloc-stdlib
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1397137-31052/root/chroot_tmpdir/scmroot/rust-alloc-stdlib'...
$ git fetch origin 508f30a9cfc36fca8fd17179cdc700c7614051d3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-alloc-stdlib
 * [new ref]         508f30a9cfc36fca8fd17179cdc700c7614051d3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 508f30a Update to version 0.2.2; Fixes RHBZ#2125983