Other than unit tests, the `paths` argument is always null -- so the standard list _is_ already hardcoded right here on line 323.  So one alternative would be to just move this `if` up into the `!paths` case (i.e. if a list of paths is explicitly provided by unit tests, we ignore the `reloadWithoutUserExts` flag and use the list verbatim; the flag would only be respected when using the default set of paths.

I like that a little better since it's actually hard to guess what the correct response is when the array contains unexpected additional elements -- are those elements more similar to "default" (i.e. we should still load them even in safe mode) or are they more similar to "dev"/"user" (we shouldn't load them)?  Impossible to know if we don't know anything about them...