The "Store Ports" remix of Thunderbird is a 100% open-source, independent program and may have a telemetry service enabled you should be aware about. For information on these programs, please visit https://wiki.mozilla.org/Telemetry for guidance.
In addition, your Windows installation may send program crash information and diagnostics [to both the Store publisher of this app (Store Ports) and Microsoft] depending on your Windows 10 Diagnostics & Feedback settings. Luckily, these settings can be altered by you, the end-user. If you do not wish to share program crash information and diagnostics from this program to the Store publisher of this app (Store Ports) or Microsoft, access your Diagnostics & Feedback settings on your Windows 10 device under "Settings < Privacy [< Windows permissions] < Diagnostics & Feedback" or enter 'ms-settings:privacy-feedback' in your address bar.