Play .m4a Extension in Web GUI

The online GUI will open a player for .mp3 files. However for .m4a it opens the download screen. How can I get .m4a files to play in the browser like .mp3.

.m4a does not require a license like .mp3 does it is openly licensed correct?
(.mp3 owners stopped requiring a licenses a few weeks ago.)

not relevant to your situation, but the mp3 licenses are now not covered under any applicable patents in the EU (2012) and US (2017)