JSON-LD
JSON-LD is a block of code that tells search engines and AI the facts about your page.
Visitors never see it. It sits in the page's head, apart from your text and design.
That makes it easy to write, check, and update.
Google recommends it for structured data. It also lets you give each thing its own @id, so one fact can point to another.
The name stands for JavaScript Object Notation for Linked Data.