Trying to start my wiki and preferring using Markdown, I have created my home using the .md extension as specified here: https://confluence.atlassian.com/display/BITBUCKET/View+and+edit+pages
Pushing and accessing the wiki, bitbucket would tell me my Home page doesn't exist. Changing the extension of the page to .markdown resolved the problem. My Home page would show in the wiki.
So the .md extension (and maybe others) is not recognize by bitbucket wiki