enigmail 1.9.8 in Ubuntu 16.04

[Ralf Mardorf]

On Mon, 28 Aug 2017 12:48:13 +0200, Ralf Mardorf wrote:
>On Mon, 28 Aug 2017 11:23:33 +0100, Phil Dobbin wrote:
>>On 28/08/17 11:10, Ralf Mardorf wrote:  
>>> Obviously you are using a third party repository.    
>>
>>I installed it via Add Ons in Thunderbird.  
>
>In the meantime I noticed that Mozilla software allows to install so
>called xpi files. So again, there is no official Ubuntu upgrade
>available, it's required to install from another source. Much likely
>Mozilla
>https://addons.mozilla.org/en-US/thunderbird/addon/enigmail/ is a
>partway secure way to get it. However, to install something OpenPGP
>related from a download, without checking it against an OpenPGP key is
>idiotic and ridiculous.

Maybe Mozilla software verifies the downloads automatically.

Does Mozilla software use a mechanism to automatically verify addons
against a key?