http://www.7-zip.org/sdk.html http://www.7-zip.org/sdk.html This one states the contents of the sdk is in public domain. It seems to apply only to the core lzm

http://www.7-zip.org/sdk.html http://www.7-zip.org/sdk.html This one states the contents of the sdk is in public domain. It seems to apply only to the core lzma compression/decompression code, not to the full 7-zip util (which, I agree, is covered by the GPL). One would have to check more precisely, but I suppose the Adobe guys did that.