Re:A plain text note-taking system for problem solving
by jonsen on Sunday August 08, 2021 @05:04AM
(#28105223)
Thus, representations such as SGML, RTF, HTML, XML, wiki markup, and TeX, as well as nearly all programming language source code files, are considered plain text. The particular content is irrelevant to whether a file is plain text. For example, an SVG file can express drawings or even bitmapped graphics, but is still plain text.:
https://en.m.wikipedia.org/wiki/Plain_text