TeXmacs 1.99.12 released. (Not based on TeX/LaTeX. Not based on Emacs.)
texmacs.org
texmacs.org
A little bit from 2016: https://news.ycombinator.com/item?id=11103012
Quoting: GNU TeXmacs is a free scientific editing platform designed to create beautiful technical documents.
It provides a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content, slides, etc.
TeXmacs can be used as a graphical front-end for many systems in computer algebra, numerical analysis, statistics, etc.
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.
Its rendering engine uses high-quality typesetting algorithms so as to produce professionally looking documents, which can either be printed out or presented from a laptop.
New styles can be written by the user and new features can be added to the editor using the Scheme extension language.
Runs on all major Unix platforms, MacOS, and Windows.
Exactly, a unanimous decision from all search engine results show that this is indeed the worst naming of a TeX-related tool I've seen and it is easy to get confused with MacTeX and TeXmacs even though the latter isn't even based on using a TeX distribution.
I've downloaded and for it being a WYSIWYG it has great potential for making TeX easier to user rather than remembering the arcane language of TeX for just typesetting documents.
TeXmacs is one of the very few WYSIWYG editors that has a passable equation editor. I bit the bullet six years ago and learned LaTeX because I absolutely despise MS Word's and OpenOffice's equation editing features, but if I had known about TeXmacs at the time, there's a chance I would be using that instead.