"SEA was attempting to retroactively declare the ARC file format to be closed and proprietary. Katz received positive publicity by releasing the APPNOTE.TXT specification, documenting the Zip file format, and declaring that the Zip file format would always be free for competing software to implement."
https://en.wikipedia.org/wiki/Phil_Katz
"SEA was attempting to retroactively declare the ARC file format to be closed and proprietary. Katz received positive publicity by releasing the APPNOTE.TXT specification, documenting the Zip file format, and declaring that the Zip file format would always be free for competing software to implement."