I think I said this over HipChat, but GitHub apparently converts all tab characters to `&nbsp;&nbsp;` in the web display. The only way to know for sure whether I used a tab is to slap a `.diff` or `.patch` suffix on the pull request URL and download a diff or git patch.

It kind of sucks that this isn't configurable in the GitHub web UI. I followed the existing whitespace convention as well as eclipse allowed (tabs to get as close as possible without overshooting, then spaces to align if not directly on a tab stop).