A Mozilla Thunderbird plugin to improve integration with ProtonMail Bridge.
ProtonMail adds X-PM-* headers to your mail to indicate whether it was end-to-end (E2E) encrypted and whether it came from another ProtonMail address, but these aren't easily-visible in Thunderbird. This plugin shows you the encryption status of each email as you view it. There are four statuses:
To build from source, run e.g.
cd source
zip ../protonmail-header-display.xpi *
Open source, licensed under the GNU General Public License v3.0 or later.
Icons made by DinosoftLabs from Flaticon, used under the Flaticon License.