There is some worst problem with Firefox for android's management of storage data. When I click on translate a page, it download some pack of the source/target languages and keeps it in app's data permanently. The language also does not show as been downloaded in the translate setting section. Unwantedly firefox consumes persistent storage only for just after we randomly to translate a page from a random language and firefox android download unwanted languge's pack and event does not show in downloaded languages. No way to clean the storage apark from "clear data" which we do not want to do ! Same happens when you have an incognito session with multiple tabs open, and the system closes Firefox when you open some other apps. Firefox loses track of the "potentially to be deleted" data. Firefox data increased forever after such a Hard closed session.(in low RAM device 3-4GB). No other option except to Clear Firefox's data!