Generally each software will have its own avenue of bug reporting. Mozilla probably has their own bug tracker for Thunderbird, you should post there. Smaller projects might have a GitHub issues tab.
Reproducibility is much more valuable than logs, but logs are good too. You should include the software version, your OS version, and other details about your system that are relevant to the specific problem. For yours, you might want to include a sanitized copy of the email.
Gz on 1.0!!! And, nice gallery :)