thoughtbot/bourbon — pull request #95 by frankzilla (2012-04-29 11:17:49+00:00)
Title: Removed -moz-border-radius and -mox-box-shadow as Firefox 3.6 reached EOL.

Yay for the gradual death of vendor prefixes.

Here is Mozilla's official announcement, https://blog.mozilla.org/futurereleases/2012/03/23/upcoming-firefox-support-changes/