Rated 5 out of 5 stars

I use this add-on several times every single day, and I have for a couple of years. It is my constant companion on Thunderbird 60 for Mac OS, and earlier versions.

Given the way my email is set up, I often want to look at custom headers like `X-Original-To:`. Sometimes, I want to check the `Received:` headers to make sure the message came from where it says it did. Toggle-Headers makes it easy: I just type 'H' and all those headers appear where just a few headers were before.

The developer, mattsch, is responsive. I wrote an email recently to the support address, and got a reply from the developer, meeting my needs.

There is a new version of this add-on supporting Thunderbird 68, so when I upgrade, Toggle-Headers will be ready for me.

This review is for a previous version of the add-on (2.0).