What the grade means
The grade from A to F answers how complete the passport is. But the grade is not what decides whether it may be published — the mandatory fields are.
The fields the regulation requires for the product's category. If one is missing the passport may not be published, however high the grade.
That the passport can be reached and read by a machine: EN 18216 access, EN 18219 identifier, EN 18221 versions, EN 18223 header fields.
The grades
How the score is calculated
The score is the share of fields filled in, weighted. Mandatory fields carry 70 of 100, optional ones 30. If a category has only mandatory fields they carry the whole hundred.
Example: ESPR Base — 17 mandatory and 47 optional fields.
The last row is why the letter is not the answer: a passport can be almost complete and still be missing the one thing that is required.
The two numbers on the result page
What the passport contains, measured against the category's field list. That number gives the letter.
How the passport is delivered, not what it contains: address, content negotiation, versions, header fields. Each check points at a clause in an EN standard.
What counts as mandatory
It depends on the product. A battery is measured against Annex XIII of the Battery Regulation, a jumper against Article 7 and Annex III of the Ecodesign Regulation. Every field carries the reference to the provision that requires it.
A field is mandatory when a provision requires it. Product name, brand and model number are: the regulation requires the product to be identifiable. Size and colour are required by no provision — they exist so a person recognises their own item, and count as optional.