Rsyncable goes further: instead of having fixed size blocks, it makes the block split points deterministically content-dependent. This means that you can edit/insert/delete bytes in the middle of the uncompressed input, and the compressed output will only have a few compressed blocks change.
zstd also has an rsyncable option -- as an example of when it's useful, I take a dump of an SQLite database (my Home Assistant DB) using a command like this:
