There are several options, depending on what you would like to do:
- There are no "default" or preset layers available to be used in the API. Each instance needs its own configuration of layers. For those who would like to only get DATE information, you can create a layer returning white (e.g. "return [1,1,1];") and append the "DATE" layer in your request.
- You can use a feature info request and point to some location. The response will contain a date field within it.
- You can use the WFS service with the same parameters as used in your WMS request (e.g. date, cloud coverage). You will get a list of features representing scenes fitting the criteria.