Cloudflare deploys Zstd, and many web servers and CDNs use it. Endless possibilities for Facebook and US gov. They can put Yann Collet out of the way or gag order him.
LZMA is the highest compression algorithm outside of PAQ and SuperRep+LOLZ, while being magnitudes faster than both. Zstd compression ratio is a joke and is only good for webpage asset loading times.