The existence of DRM in a format is usually the reason something doesn't get supported, usually due to licensing or patent issues on the DRM, if not because of

The existence of DRM in a format is usually the reason something doesn't get supported, usually due to licensing or patent issues on the DRM, if not because of philosophical/political/social issues around supporting DRM itself. Do you mean to suggest that Mozilla would be/should be/are subject to third-parties who want to restrict access to only DRM-supporting formats (I honestly don't know if they are, but it seems unlikely)? It's not like Mozilla has a music store and needs access to publishers/distributors that will only get on board if there's DRM. Support for more formats can only serve to help Mozilla's users and their market penetration (even if supporting more formats is more of a burden, development- and support-wise).