Hello:

This is a message where I try disabling text formatting.

Before this line a left one empy line.

Before this line a inserted two empty lines.

These are two lines without emtpy lines between them.

This is the second line.

It depends on what style it takes. There is a bug in Thunderbird html editor that makes style "preformatted" to do just that unless you use the proper incantation. It's a bit tricky. I am this instant on an ancient Leap install, TB 91.4.0, so my testing now would be irrelevant.

--
Saludos/Cheers
       Carlos E. R. (using Leap 15.2 on Andor)