Download of Metion 2.4.8 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free software for Mac is Z.R.E.Y. The program lies within Productivity Tools, more precisely Office Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
Metion is a notebook tool that focuses on the writing experience. Therefore, it uses Markdown as basic text syntax. Writing experience does matter for Metion. Consequently, the utility has redesigned the writing-focused mode named "Zen Mode" for macOS. Choosing a background image that suits your mood, the white noise of Zen Mode is great, and the writing-unrelated interface elements automatically disappear.
You may want to check out more Mac applications, such as PDFMergeThing or iTeXMac2, which might be similar to Metion.