Thanks! I was also surprised that there are very few tools to work with the seekable format. I could imagine that at least some people have a use-case for it.

Yes, the name is a combination of zstd and seek. Funnily enough, I wanted to name it just zeek first before I knew that it already exists, so I switched to zeekstd. You're not the first person asking me if there is any relation to zeek and I understand how that is misleading. In hindsight the name is a little unfortunate.