Don't force timezone=UTC when creating new calendar events
Currently, TorBirdy sets the Thunderbird internal timezone to UTC to avoid leaking the user's location when sending emails. However, this carries through to the Calendar functionality [1] and now when I create a new event it defaults to Europe/London timezone.
For usability, this should still be in the user's own local timezone - I think there is not much security value in forcing this to UTC for everyone since you're already trusting your calendar provider with quite a lot of information. (Or at least default to local tz, and allow the user to explicitly override it to UTC.)
[1] This was integrated into recent Thunderbird versions, you should be able to see it in your "add-ons", as either "Lightning" or "Iceowl" (Debian).
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