How we build the thing that publishes your changelog, your blog and your release notes.
There is no negotiated version number for a tool surface. That makes the rules simple and strict: add freely, never redefine a name, and put the migration note where the model will read it.
A product changelog is read by people who will see the change on screen. An API changelog is read by people whose code will stop working, and that audience needs the symbol name, the date and a feed a machine can poll.
A breaking change is the one entry a reader cannot skim. It has to name what stops working, the date it stops, and the replacement — and no common changelog standard gives it a category of its own, so the title and the body carry it.
Market4 turns one release note into a changelog page, a blog post, a mail-out and a week of social posts — and then tells you which of them brought anyone back.