If your document editor represents documents as a stack of edit-events (for undo/redo or whatever) and you document every nook and cranny of this "document format", standardize it as "binary event-sourced document format, .esd" then your binary spec will be very close to a full description of your document editor. Everyone who wants to use your format now has to reimplement your editor.
Anyone can leak implementation details into any format, and it is to some extent unavoidable, but if you can make it readable (or semi-readable), some thought has at least been put into the representation.