Words a Markdown renderer leaves off the page
A Markdown comment, or the title of a link: in the file, read by every model handed the file, and shown by nothing that renders it.
How the text is hidden
Markdown has no comment syntax, so authors use a link reference definition that nothing links to: [//]: # (like this). A renderer removes every definition from the page, whatever it holds. Any definition can also carry a title, and so can an inline link or image, [words](address "like this"), where a renderer puts the title in a tooltip. In each case the words are ordinary text in the file and are absent from the rendered page.
Why a model still reads it
A text file is handed to a model as it is. Nothing renders it first, so the model reads the definition and the title along with everything else, while a person reading the same file on a repository page, a documentation site or a chat window sees neither.
What we do about it
The text parser finds link reference definitions and inline links across the whole file, and reports only the part that can hold prose: a title in any of its three quotings, on the same line or the next, or a destination in angle brackets that contains a space. Each becomes a run with the reason non-rendered-part, and the pack rule txt-markdown-unrendered reports it at informational with action flag. It is kept in text.canonical, because a person who pasted the file was looking at it. containerVisibility is editing-only, since a text editor shows it. Text written as an instruction escalates. An HTML comment in the same file is found separately, by reading the file a second time as a browser would, and is reported as html.comment.
How often it fires
0.24% of 822 real text files — 328 public-sector text files (GovDocs1) and 494 developer documentation files (README, changelog, licence), measured 2026-09-29.
This is an alert-volume number and nothing else. It says how often the alarm sounds on documents as found — not how often it is right, and not whether what it found was harmless. Documents as found may themselves carry concealment. Read it against the population named above rather than as a property of documents in general.
Check your own file
Three commands: a key, credit, a verdict.
Start with the API