We have a page that lists all of the key-value pairs that are used, and which of the specifications require them / have them optional / etc. Here are a couple things that could improve the layout / clarity of the table (originally mentioned in #198

• I think the table should be transposed. The columns will continue growing while the rows probably won't, and already we have a wider-than-higher table, which I think would render better if it were transposed. This is pretty easy to do with a little pandas, happy to try helping out here.
• Could we add lists to the bottom of this table that include the list of extensions associated with each type of file? I think that'd make the table a bit easier to parse since currently some cells are a lot bigger than others.