librsync has relocated from samba.org to sourceforge.net. Visit that site to download the source, find the mailing lists, report bugs, etc.
librsync is a free software library that implements the rsync remote-delta algorithm. This algorithm allows efficient remote updates of a file, without requiring the old and new versions to both be present at the sending end. The library uses a "streaming" design similar to that of zlib with the aim of allowing it to be embedded into many different applications.
librsync is currently pre-1.0, with most important functionality working.
librsync is not wire-compatible with rsync 2.x, and is not likely to be in the future.
This is a new codebase, designed to allow a fresh start on the problem and a cleaner design. It may be used in a future version of rsync or a successor project. Early steps towards that are visible in Wayne's rZync prototype, and Martin's superlifter design.