Complex sentence: This add-on opens the ePub file just like you can open PDF files in the Firefox browser and creates a user's private library, which includes the files opened on a website or from the local disk.
Split into simpler sentences: This add-on opens the ePub file just like you can open PDF file in Firefox browser. The add-on creates a user's private library, which includes the files opened on a website or from the local disk.