On Firefox, when private mode is enabled, it prevents the extension from loading.
I've got the following error message : [7TV] [ERROR] <IDB> Failed to open database InvalidStateError
It seems that Firefox disables IndexedDB in private mode, see : https://news.ycombinator.com/item?id=26819332
jffry
By default in Firefox, indexedDB is disabled in private browsing mode (dom.indexedDB.privateBrowsing.enabled=false in about:flags), so you can detect it with something like var db = indexedDB.open("test");
db.onerror = () => console.log('private browsing');
db.onsuccess = () => console.log('not private browsing');
Based on Bugzilla, it see...