[WhitneyLand]

Is it really not a good idea per se, or simply that it would need to be more prescriptive?

For example a new extension could mandate minimum support for codecs or features. Like wp explains, matroska file extensions are .MKV for video (with subtitles and audio), .MK3D for stereoscopic video, .MKA for audio-only files, and .MKS for subtitles. I’m not aware of any reason an extension couldn’t represent minimum package requirements, like audio/video/at least av1 codec, etc, that would work for most cases, while potentially still retaining extensibility where practical.

[aepiepaey]

But then you're not really naming it after the codec.

Instead you create a standard that mandates container X, support for video codecs Y[, ...], and support for audio codecs Z[, ...]. Then you can document a player/device as supporting that standard and also name video files after it.

[WhitneyLand]

Thank you, that’s correct. I was questioning an argument you made in a way that was not technically analogous.

The gist of the comment should have referred only to what I brought up, which as you point out is a minimum simple standard for packaging and contents as it could relate to a file extension.