PGP/MIME option not enabled in Chrome

[seisvelas]

In Firefox this appears as expected:

However, when I do the same thing with Chrome, it doesn't appear:

Is there something additional that needs to be done for the option to appear in Chrome?

Ref: https://mail.google.com/mail/u/1/#inbox/FMfcgxwJXLmlLTrbmXgLNrDCBnHmRLCM
Ref: https://mail.google.com/mail/u/1/#inbox/FMfcgxwJXVFkFWwPcFhjPFKDRVWjhkML

[seisvelas]

Additional question: When do we expect to have this available for Chrome users?

Ref: https://mail.google.com/mail/u/1/#inbox/FMfcgxwJXpPkXPlfKWClmxRBcWTSCsvZ

[tomholub]

blocked on #3032

[tomholub]

from @bilalashraf123

4- By default the message format could be PGP MIME. MIME is more of the adopted standard. Also the only format supported for SMIME is MIME.

Here is the relevant issue caused by Gmail API, more details at #3032 and #3157

S/MIME is not affected