Setext was first introduced in 1991 by Ian Feldman for use in the TidBITS electronic newsletter.
To prevent errors, most large setext publications are created using a markup language such as HTML or SGML and then converted.
The setext document can then be distributed without the need for the recipient to use a HTML email or web viewer.
After several months, it was clarified[3] that this tag was not an official part of setext, and that multiple documents should instead be delimited by $$ appearing at the end of a line of text.
This is primary body text, generally plain undented in emails, etc.