They define a property template or schema, defining the properties that will be used by all channels based on the provider.
The specific values in the provider serve as default values for channels.
If the property is not defined in channels based on this provider, the default value is used. If the default value is overridden by setting the value within the channel definition, then that value is used. By customizing a provider’s property values, you can customize all channels that the provider generates.