Firefox return maybe for audio/mpeg and probably for audio/mpeg; codec="mp3" (Firefox 42 OSX 10.10.5)
Speficy codec name to fix Firefox mp3 support test
Build details: https://travis-ci.org/modernizr-savage/Modernizr/builds/88371775
(Please note that this is a fully automated comment.)
"Generally, a user agent should never return "probably" for a type that allows the codecs parameter if that parameter is not present."