caskroom/homebrew-versions — pull request #452 by htian (2014-10-02 23:30:44+00:00)
Title: Update Thunderbird Beta to 33.0b1 (Sep 24, 2014 version)

Thunderbird Beta was updated without a version number change on September 24, 2014

Source: https://download-installer.cdn.mozilla.net/pub/thunderbird/releases/33.0b1/mac/en-US/