Calendar.parse_utc_datetime

You're seeing just the callback parse_utc_datetime, go back to Calendar module for more information.
Link to this callback

parse_utc_datetime(arg1)

View Source (since 1.10.0)

Specs

parse_utc_datetime(String.t()) ::
  {:ok, {year(), month(), day(), hour(), minute(), second(), microsecond()},
   utc_offset()}
  | {:error, atom()}

Parses the string representation for a datetime returned by datetime_to_string/11 into a datetime-tuple.

The returned datetime must be in UTC. The original utc_offset it was written in must be returned in the result.