YAML
A text format for configuration and data, with indentation for structure. Home Assistant uses it for its configuration files, and much more.
- In code
configuration.yaml.yaml
You meet YAML in many places as a contributor: configuration.yaml, automations and scripts, services.yaml of an integration, the configuration of an app, the sentences of the intents repository, and the examples in the documentation.
The documentation has its own YAML style, so every example looks the same.