On Windows (8.1) this extension works impeccably. It is indispensable for markdown viewing around the web and on local files.

That being said, I had issues making it work on Ubuntu (21.10). None of the solutions on the README page seemed to work (although it did previously). Finally (after many hours) I found the culprit: the snap installation of Firefox. After removing this problematic snap installation and reinstalling Firefox via get-apt, it started working again.

If I had this extension on Windows only, then I'd give it 5 stars hands down. However, the lack of a streamline installation on Linux systems brings it down to 4 stars. Nonetheless, it is an excellent extension imperative for markdown files.

Extremely useful extension for viewing local .md files as HTML! And the Table of Contents feature is indispensable!! Thank you!

I had a Markdown file (*.md) on disk I needed to render and print. It took about 30 seconds to install this extension, drag-and-drop the file onto a Firefox window, and boom, there's the rendered version of the file displayed as intended. I'm using Firefox 84.0.1 on Windows 10. Thank you!

great extension!

This used to work really well. With firefox 83.0 on OSX 14.1 it cannot render a local file. I wasted way too many hours trying all the work-arounds described in the github page and on superuser. None of them worked.

The syntax highlighting options are nice, but if you have an URL in a code block, the double-slash is interpreted as a JS comment.

Excellent

I had to follow the instructions on the home page to set up the markdown mime type on linux, and with that it works marvelously.

Does not work if the .md extension is in upper case.

Considered installing but the excessive permission requirements put me off.
Please be clear WHY the extension needs 'Access your data for all websites' as a permission requirement if it will be accessing only local data.

Not working!

It took me a while to even get it to do anything. I would appreciate proper instructions on how to use the extension.

This is not a problem with this extension, rather with Firefox. Whenever I open markdown files in firefox, it just wants to download them. I ended up having to change the mimetype text/plain to also include the extensions .md and .markdown. See here: https://superuser.com/questions/696361/how-to-get-the-markdown-viewer-addon-of-firefox-to-work-on-linux/1175837#1175837

The way the superuser article fixes the problem involves making all markdown files part of the text/plain mimetype but other apps on KDE (and possibly other 'DEs) use the text/markdown mimetype differently than text/plain. So I went into about:config and changed helpers.private_mime_types_file to a custom file (e.g. ~/.firefox-mime.types) to separate firefox's mimetypes from my system. I then added "text/plain md markdown" in that file. The problem is due to the way firefox handles files and mimetypes.

I am unable to change the code style in the markdown-viewer menu which is very frustrating, the markdown style does work.