"Documents can be saved in TeXmacs, Xml or Scheme format and printed as Pdf or Postscript files. Converters exist for TeX/LaTeX and Html/Mathml. Notice that TeXmacs is not based on TeX/LaTeX." (ib., 2019-10-14)
"Toast UI Editor", GFM Standard + Chart & UML Extensible.
nvu and compozer successor