MarkText 0.17.1 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The program is included in Productivity Tools. This free software for Mac OS X is a product of MarkText.
From the developer:
MarkText is an MIT licensed open source project. The application provides real-time preview and a clean and simple interface to get a distraction-free markdown writing experience. The tool supports markdown extensions such as math expressions (KaTeX), front matter, and emojis. It supports paragraphs and inline style shortcuts to improve your writing efficiency. You can output your project to HTML and PDF.
You may want to check out more Mac applications, such as Mark Text, which might be similar to MarkText.