If you configure Apache to enable gzip compression for your static HTML/CSS/JS/etc. files, it automatically outputs a gzipped version to any client that sends an appropriate Accept-Encoding request header. (And for other clients, it just sends the raw uncompressed file.)
My question is: does Apache recompress the raw file every time it is requested by a gzip-accepting client? Or does it cache the gzipped copy, and only recompress it if it notices the last-modified time on the file has changed?
And if it does cache a gzipped copy of your files, where is this cache stored?