On a git submodule update on HEAD, I get: fatal: reference is not a tree: 85ece0f8653e7b1e7de6024d372cfeaf36ab5fa9 Unable to checkout '85ece0f8653e7b1e7de6024d372cfeaf36ab5fa9' in submodule path '.arc-linters/arcanist-external-json-linter' Edward