Frontmatter is added as a header when creating a new Hugo file via hugo new file_name it has the following format:
--- title: "Frontmatter" date: 2019-12-30T12:01:10+01:00 draft: true ---
It contains information about the file in key/value pairs.
Can be written in JSON TOML, YAML
- toml is selected. Similar to yaml
- json can be used but heavy
custom variables can be added, eg