Object
If you have lots of frontmatter fields you can group them with an object. Objects look like this:
properties:
date: 2021-10-17
category: news
This object will be represented in the CMS as:
properties (2 key/value pairs)
When you click this object it will show a new page with date and category input. When you click “save” the changes will be saved (but not yet committed or published).