a Source|Rendered switch that shows "Rendered" by default, except when the URL anchor starts with #L, which means line number anchors now work to link to specific lines in Markdown source!
a file size limit of 10MB on client-side rendered files, so we don't force users to download huge files,
and a .blob-viewer[data-type=simple] that rich JS viewers can fall back to when the rich rendering fails for whatever reason. They should hide() their own blob viewer (.blob-viewer[data-type=rich]) and the switch buttons (.js-blob-viewer-switcher), and show() that simple fallback viewer, which will be the regular Download or Text view.
To do:
Split up in a sensible way
Specs
The switch can be seen in action with SVG, but also supported for Markdown and IPython Notebooks, as well as other supported Markup formats:
