Problem/Motivation
The recipe at /core/recipes/example/recipe.yml isn't a functioning recipe and thus provides a bad example.
It also contains a composer.json file which it doesn't need to.
This was noticed by @jnicola in #3446080: [PP-2] Recipes UI (comment #10) as it broke recipe discovery.
Steps to reproduce
Try to apply /core/recipes/example
Proposed resolution
Make it a functioning recipe.
Remaining tasks
Fixing it.