This is the PHP extension for Brotli, a generic-purpose lossless compression
algorithm that compresses data using a combination of a modern variant of the
LZ77 algorithm, Huffman coding and 2nd order context modeling, with a
compression ratio comparable to the best currently available general-purpose
compression methods. It is similar in speed with deflate but offers more dense
compression.

This extension can also transparently compress objects stored in
APCu cache. Just set apc.serializer=brotli in your php.ini.