About .7Z File Format
To do word count in 7Z archives, let’s get to know a little more about this format.
7z is a modular, versatile format, that supports many compression and encryption types. It initially appeared in the open-source 7-Zip archiver. 7-Zip is publicly available under the terms of the GNU Lesser General Public License.
7-Zip can also open many other archive formats, including executable installer files.
WinZip and WinRar can also open 7Z files?but only in read-only mode.
Link:
WinZip Home Page
7-Zip Home Page
WinRAR Home Page