Rated 5 out of 5 stars
Did the job and it just looks way better now. The Text is not squeezed together anymoreThis review is for a previous version of the add-on (0.0.1).
Rated 3 out of 5 stars
Unfortunately this did not work for me with Thunderbird 78.13.0 under Ubuntu 20 LTS. It made the fonts smaller. But it did not enlarge the space (padding) between the lines.
What worked for me was another add-on with a similar name: https://addons.thunderbird.net/en-US/thunderbird/addon/larger-message-list/
Now there is more space between the messages in the list. This is much easier to read.
I can not really rate this Add-on here, but as the site insists I have to rate it, I give it three stars. I hope it does work for others.