$ git clone -n https://src.fedoraproject.org/rpms/rust-allocator-api2.git /var/lib/mock/f38-build-side-43-rust-devel-1416881-31457/root/chroot_tmpdir/scmroot/rust-allocator-api2
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1416881-31457/root/chroot_tmpdir/scmroot/rust-allocator-api2'...
$ git fetch origin dbcc7895e44cfe37cfa5c85e0afea8096fd244cf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-allocator-api2
 * [new ref]         dbcc7895e44cfe37cfa5c85e0afea8096fd244cf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dbcc789 Update to version 0.2.16; Fixes RHBZ#2222886