read.amazon.com doesn't work in TBB
Amazon made a Kindle HTML5 webapp! With enough throwaway accounts and gift cards, I might soon actually be able to read books again in a way that is consistent with my assortment of self-diagnosed mental disorders! Well, except for the one that I contracted from RMS that tells me I won't really own any Kindle books I buy because they can be taken from me at any time for any reason... But still, it's been so long since I've been able to read a book in private, I might actually be willing to rent the right to read if given the chance...
Philosophical objections aside, none of this really matters in a practical sense, because read.amazon.com tells me to "turn off Private Browsing Mode" in order to use it with TBB.
Tweaking random prefs makes this appear to be related to the fact that we disable DOM storage and/or offline storage. Re-enabling both of those things allows it to work again. Disabling offline storage seems to allow it to still work (at least well enough to redirect me to a login page), but the behavior is different.
We have #6564 (closed) for DOM storage. I'll also create a ticket for offline storage and cross-reference them here so we can make sure this site works.