Thanks for all the about:support Thunderbird add-on feedback, especially from Eric Moore!
Siddharth Agarwal, developer of the about:support add-on code, is about to start the process of landing about:support in the main Thunderbird product i.e. converting it from an add-on to a core part of the next release of Thunderbird, codenamed Miramar (Miramar is still in alpha and is only for those who are comfortable with alpha software and how to backup and restore their email and address book).
We’ll continue improving it (including further condensing the plain text output as per Eric’s feedback) and would love further feedback on about:support.