https://stackedit.io/
StackEdit – In-browser Markdown editor
Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.
stackeditbrowsermarkdowneditor
https://graphizm.fr/markdown/code-md/blog/tag:Stackedit/
StackEdit - Documents Markdown
stackeditdocumentsmarkdown