$ git clone -n https://src.fedoraproject.org/rpms/rust-bstr.git /var/lib/mock/f39-build-1466657-33688/root/chroot_tmpdir/scmroot/rust-bstr
Cloning into '/var/lib/mock/f39-build-1466657-33688/root/chroot_tmpdir/scmroot/rust-bstr'...
$ git fetch origin 95e2d633b78429e059f07eefee53d9aca9195d07:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bstr
 * [new ref]         95e2d633b78429e059f07eefee53d9aca9195d07 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 95e2d63 Update to version 1.7.0; Fixes RHBZ#2242963