I don't recall that earlier versions of TB prior to the version 78 spinoff did this, but perhaps I wasn't paying attention?Thunderbird Collects Data To:
Improve Performance and Stability For Our Users
Thunderbird collects telemetry data by default to help improve the performance and stability of Thunderbird. There are two types of telemetry data: interaction data and technical data.
Interaction data: Thunderbird receives data about your interactions with the application, such as whether calendars and filters are being used, and how many email accounts a user has.
Technical data: Thunderbird also receives basic information about your device and application version, including, hardware configuration, device operating system, and language preference. When Thunderbird sends technical data to us, your IP address is temporarily collected as part of our server logs.
Read the telemetry documentation and learn how to opt-out of this data collection here.
Set-Up and Configure Your Email
Thunderbird collects your email domain and other technical data to set-up and configure your email account. Other information, like your name, your email messages, and your account’s address book are stored locally on your computer and never sent to us. Learn more here.
Email domain: Thunderbird receives your email address domain. Your full email address is never processed or stored on our servers (unless you choose to share it when you send a crash report).
Technical data: Thunderbird also receives information about the application’s version and device operating system. When Thunderbird sends technical data to us, your IP address is temporarily collected as part of our server logs.