Link file formats to existing format registries

@wader wrote:

I wonder if some formats in fq could have links to these projects? currently format refrences are kept in <format-name>.md ex https://github.com/wader/fq/blob/master/format/mp4/mp4.md#references

I think the best registries of file formats to link to are

• Just Solve the File Format Problem
• Wikidata (currently with ~14.000 formats)

Both can be edited freely and both link to other registries such as PRONOM. Wikidata further contains more structured information such as default file extension and MIME Type. I once wrote a Wikidata module for jq this may help to get information from Wikidata (e.g. MP4).