@ancient-stone-50795: @red-cpu-25099 I still maintain that adding a subsystem config to limit the allowed extensions of BUILD files is (1) A reasonable feature to add regardless (2) Doesn't muck with the mildly delicate and very import logic of spec_excludes and (3) solves the concrete problem at hand that is causing issues (ignoring BUILD.md, some other build system's checked in BUILD file, with which we don't actually have overlap in practice)