All software in this path is released under LGPL by Igor Pavlov; sfx icons were substituted from ones created by myself.
Rar29.dll (Rar29.so on Linux systems) brings additional restriction: the unRAR sources cannot be used to re-create the RAR compression algorithm, which is proprietary.
If you don't need to handle Rar format you can simply remove it.

Reference: http://www.7-zip.org/