Unable to expand ".zip" into "downloads" (Error - 63 file name too long.) Unable to expand "zip" into "downloads" (Error - 63 file name too long.) on my MacBook Pro with OS X 10.9.5.
If you install Better Zip or Pacifist Zip, you will be able to open the zip file and inspect the contents, file by file.

The file with the problematic long name - including folder names -  should be evident. If not, you can then extract the files one by one until you find the one(s) with the long name which are causing the problem.

You can rename the problematic files when using Better Zip and then resave the zip file.

http://macitbetter.com/ Better Zip

https://www.charlessoft.com/ Pacifist Zip