ZIP Reader is an add-on that help you easily unzip a compressed file.
Simply drag & drop a zipped file to a designated area in the app UI (top section). All the zip content will be listed in the UI. You can download each individual file by clicking on it or download all files to single folder.
Note #1: this add-on is only designed for "reading" a ZIP file. For the inverse operation (zip a folder), you need to use a different application. There is also a reload button at the top left corner in the app UI. Clicking on this button will reload the app. If you want to extract multiple zip files, please do this one by one. It is also recommended to reload the UI after each unzip operation.
If you see any bug, or have a feature request in mind, please fill the bug report form in the add-on's homepage (http://mybrowseraddon.com/zip-reader.html).