Wow, impressive work. Thanks for posting this. For the curious there is more detail about this standard over here:
https://facebook.github.io/zstd/
It seems to focus on small data, and can be trained for specific data which is really interesting (and potentially useful for things like image or html compression specifically) - sounds similar to brotli in that sense:
To solve this situation, Zstd offers a training mode, which can be used to tune the algorithm for a selected type of data. Training Zstandard is achieved by provide it with a few samples (one file per sample). The result of this training is stored in a file called "dictionary", which must be loaded before compression and decompression. Using this dictionary, the compression ratio achievable on small data improves dramatically.
How would you compare the two, brotli and zstandard? I see they have a table where zstd edges out brotli in speed, but brotli seems to have browser adoption.