Puntuado con 5 de 5 estrellas

Works great. I regularly receive .DAT files (text files) and Thunderbird didn't know what to do with them.

This extension opened them up in Notepad, right from the mail interface.

Esta valoración es de una versión anterior del complemento (0.9.0). 

Thanks for using.

By the way, since Thunderbird 91.4.1, you can directly open ".DAT" files or such with correct viewer.

Check TB release notes from:
https://www.thunderbird.net/en-US/thunderbird/91.4.1/releasenotes/

> Temporary files created for forwarded attachments sometimes had the wrong extension