cool. although I think with 4mb window it would be more efficient. 100mb seems excessive, then I assume you wouldn't need a sliding window. (if it works well enough for 100mb)
If you create a block every Xmb... inserting a single byte at the beginning of the file will change every subsequent block.
https://github.com/Snowtrack/SnowFS/blob/main/src/common.ts#...
The intent is a simple form of delta encoding, the hope is that many chunks will be common between two versions.