TYPO3 Core

Please use .gz instead of .gzip for statically compressed files, because

1. this is far more common in the UNIX environment (.tar.gz, not .tar.gzip; in fact, I have never seen .gzip anywhere else),
2. nginx gzip_static [http://nginx.org/en/docs/http/ngx_http_gzip_static_module.html] can detect and serve .gz files.

So, compressCss and compressJs could be used with nginx gzip_static without problems.