librsync-dev 2.3.4-1ubuntu1 (armhf binary) in ubuntu mantic

 librsync implements the rsync remote-delta algorithm, which allows for
 efficient remote updates of a file, without requiring the old and new versions
 to both be present at the transmitter. The library uses a stream-based designed
 so that it can be easily embedded into network applications.
 .
 This package contains the development files.