let me try again: this bundle is about doing cache invalidation. to do cache invalidation, we need cached data - hence we have the cache.php file that serves a response that can be cached. but the 3 caching methods seem to all have the same effect, that nginx caches the response. as far as i can see, all 3 files do the same in that respect. we don't want to test if nginx properly handles max-age and expires header. we want to test if we can invalidate a cached response. so i think one of them (or the one we already use with varnish) would be enough.