IndexedDB doesn't work in TorBrowser
Just to be clear: TB 7.5.5 (FF 52.8.1), IndexedDB doesn't work at all. It exhibits symptoms similar to vanilla FF in Private Mode -- the API appears to exist, but the first call to "open" fails with InvalidStateError. TB has a 'dom.indexedDB.enabled` config boolean. It's set to enabled, yet it doesn't help at all.
On firefox side of things, there's https://bugzilla.mozilla.org/show_bug.cgi?id=781982 - they break IndexedDB in private mode on purpose and plan to fix this sometime in the future. There's also a bug/workaround - IndexedDB in FF private mode is still accessible from WebWorkers. Similar fix/workaround IS not applicable in TB - again, on purpose, from #16333 (moved).
So, I'm quite unsure what the status here is, but it would be great to fix and enable IndexedDB once and for all, as more and more sites rely on it.