Note that -
Operated by MZLA Technologies Corporation, a subsidiary of the Mozilla Foundation, Thunderbird is an independent, community-driven project that is managed and overseen by the Thunderbird Council, which is elected by the Thunderbird community.
Here is a screen-shot of latest Thunderbird (ESR) Email client: https://www.thunderbird.net/media/img/thunderbird/new/screens/mail-screen.png