This endpoint returns the details about an itinerary by hash (the unique fingerprint used to identify them). Itinerary hashes are returned in /co2/v2/plan for example.
The response is a feature collection where each feature corresponds to a leg of the itinerary. Each feature has its own properties such as the distance, the duration, the day of departure and arrival, the service id, etc. The feature collection properties are those of the entire itinerary : duration (including transhipments, wait in ports), ids of the carriers that can operate the itinerary, etc.
The distances are given in meters and the CO2e emissions in grams per TEU.