https://scotthelme.co.uk/a-new-security-header-feature-policy/

I guess it will be easy to add, because we certainly don't use any of these features.
Or maybe "gyroscope" or so may be used by the random number generator in sjcl, but that's all.

For the feature Private key transfer #1090 you use Barcodes for verification.
Would it be a good idea to use the same way to verify Public key of contacts and mark this verificated users in contactlist with a green Icon or somewhat (similar to Threema )?

Maybe:
-yellow for "I'm not sure but I trust the key anyway and will verify it by our next beer."
-green for "I have scanned the code of m

Blocked by #2