The door appends one navigation note

Decided

15 August 2026

State

binding

An HTML document is served with the author's bytes unchanged, and after them one small, visible script — the navigation note. It does one job: a relative link to a Markdown file opens that page in the product, and an external link opens the browser. Without it neither promise of HTML files can be kept, because a sandboxed frame cannot be steered from outside.

The file on disk is never touched. "Never injects" still holds for what it was written against: the product never restyles, corrects or edits the author's document — the note is appended after it, does not read or change its content, and is plainly visible in the served source.