[Someone]

It’s rsync in that it can sync directories in various ways, but AFAIK it doesn’t have its ability to send partial files if the target already has part of it.

https://en.wikipedia.org/wiki/Rsync#Algorithm:

“The rsync utility uses an algorithm invented by Australian computer programmer Andrew Tridgell for efficiently transmitting a structure (such as a file) across a communications link when the receiving computer already has a similar, but not identical, version of the same structure.”