Interesting. I've heard about cursors in reference to a Rust library that was mentioned as being similar to protobuf and cap'n proto.

Does this duplicate the name of keys? Say if you have a thousand plain objects in an array, each with a "version" key, would the string "version" be duplicated a thousand times?

Another project a lot of people aren't aware of even though they've benefitted from it indirectly is the binary format for OpenStreetMap. It allows reading the data without loading a lot of it into memory, and is a lot faster than using sqlite would be.

Edit: the rust library I remember may have been https://rkyv.org/