alt Hacker NewsI think actually this competes with the old BerkeleyDB: https://en.wikipedia.org/wiki/Berkeley_DB - which I now see is no longer BSD-licensed, and in any case has been rendered almost extinct by SQLite. It was used for basic on-disk key-value store work.
Even BerkeleyDB tries to be mutable. What I'm doing doesn't need the mutability so it's much more similar to dictionary formats (though probably simpler) than it is to a database. Though a lot of people do use full databases for immutable dictionary key-value stuff. I just couldn't get any database to work well enough for a pwa dictionary.