I am not defining here which data format language this should be presented in. It could use standard EDI formatting, XML, YAML, or any other common markup language. But it has to be a TEXT format, not binary.
Some fields should be optional (as in excluding data in them does not cause the file to be rejected. Certain others would be required
Creating this in a standard markup language will make it easier to create the file in any code editor. Additionally there could be standalone file creation applications, and extensions to word processors like LibreOffice, Calligra Suite, OnlyOffice, and others. There would likely be online services to create the file online and download when done.
The specification must be fully open and documented. Any extensions need to be added to the main specification. If additional data is needed by a particular site, the user would be prompted to add that data after successfully uploading their resume file.
This will, by it’s very nature, not be a substitute for a human-readable resume.
These are just proposed fields. The actual names of them would be codified in the specification.
OpenDocument:
Proposed_resume_exchange_format.odt
PDF/Acrobat: Proposed_resume_exchange_format.pdf