Someone reading a letter to you over the telephone starts at the top, follows the sentences in the order they were written, and does not stop to read out the address printed above them: they can see which part is the message. Software reading a document aloud sees none of that. All it has is the marks on the page, in the order the program laid them down — often the heading, then the page number, then the body — so a blind reader is given the page number in the middle of a sentence.
This document carries a second copy of itself that nobody sees: a list saying this is a heading, this is a paragraph, this is a table of three lines, and this is the order to read them in. The running head and the page number are listed there as decoration, so they are never said out loud. Nothing looks any different — open the file and you see two ordinary pages.
The file below claims no standard: it carries the structure, and says nothing about which set of rules it means to be held to. That claim is a line to add, and it is what a check is then run against — so the same example is written twice more, once claiming the accessibility rules built on the newer standard, once claiming the archival level that asks every mark on the page to stand for a letter. Each of those two goes to veraPDF before a change enters the library, and a refusal stops the check where it stands.
Nothing is left out and nothing is simplified: this is the program exactly as it runs, for the developer who uses this library. The third is the description itself: a plain list of what the page has to say, which is what the service is sent.
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Three rulers — centimetres, inches and points — on a page that tells whatever prints it to put it out at exactly the size it was drawn, and to offer nothing else. Lay a tape measure on the printed sheet and you can check for yourself.
Two sittings bound into one file. Each page carries a record of its own — what it is, whose hand wrote it, the day it was written — the photograph on the second page carries one too, and each transcription is tied to the page it transcribes rather than to the file at large.
A records office's reference, the department it came from, the date until which the document must be kept and its classification, carried inside a file an archive still accepts. No archiving rule knows what a keep-until date is, so each entry carries a description of itself, and that description is what makes a checker accept a fact you alone invented.
Every line of the note carries the order it was picked for, the article code and the shelf it came off, and prints none of them. The place where the driver signs carries the round and the van, and one beside the fold tick carries nothing but its own place.
A parts list whose first column is a picture rather than a word. Each picture carries the sentence somebody hears in its place, so nothing in the list is lost on a reader who cannot see it. On the page, the pictures are simply pictures.
The electronic invoice French law has required since September 2026: one file, a page a person reads and the same invoice inside it as XML. Nothing to reconcile afterwards, because there is only ever one invoice.
