I hear that .crx (chrome extensions) are zip files. And 7-zip says they are zip by Info->Properties button. But https://stuk.github.io/jszip/documentation/examples/read-local-file-api.html don't show listing of archive, and JSZip(data).files shows {}. Example of that file is https://www.eff.org/files/https-everywhere-chrome-2016.2.23.crx