The article needs independent sources (as in, secondary sources that are financially and editorially independent of the company who develops the .mix file type) to show that the topic warrants an article.
If an article has enough sources cited to show notability, primary sources like documentation pages can be used. If notability is not shown, then the topic doesn't meet Wikipedia's inclusion criteria and the content of the article is moot.
Without this requirement, any company would be able to publish promotional articles on all of its products, and exclusively use its own web pages as citations. Wikipedia's notability guidelines are in place to prevent spam and to ensure that topics only get articles if they can be written about in a neutral way.
https://en.wikipedia.org/wiki/Wikipedia:Identifying_and_usin...