$ git clone -n https://src.fedoraproject.org/rpms/rust-os_str_bytes.git /var/lib/mock/f38-build-side-42-init-devel-1394537-31050/root/chroot_tmpdir/scmroot/rust-os_str_bytes
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1394537-31050/root/chroot_tmpdir/scmroot/rust-os_str_bytes'...
$ git fetch origin 386ef893f6a73461d010f88d78d81fb62e5eb9a3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-os_str_bytes
 * [new ref]         386ef893f6a73461d010f88d78d81fb62e5eb9a3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 386ef89 Update to version 6.5.1; Fixes RHBZ#2214001