On 16 Jul 2016, at 22:35, Stefan Daschek wrote:

Markdown (GitHub) also uses |TM_MARKDOWN|, but defaults to (a bundled version of) |redcarpet.rb|.

This command appears to be copy/pasted from the default Markdown bundle with the fallback value for TM_MARKDOWN changed to redcarpet.rb and the MathJax support removed (or maybe it was added after Mike cloned the command).

Mike: Would it be feasible to remove the Preview command and instead have the Markdown (GitHub) bundle set TM_MARKDOWN to $TM_BUNDLE_SUPPORT/bin/redcarpet.rb?

That way, users who do not have TM_MARKDOWN set and install your bundle will automatically have Markdown → Preview use redcarpet.rb.

Users who have set TM_MARKDOWN will still get their customer markdown processor, but that is already an issue with Markdown (GitHub) → Preview.