yyyy'-'MM'-'dd'T'HH':'mm':'ss - What is the meaning of 'T' here?

Question

What is the meaning of T in this datetime pattern ?

yyyy\'-\'MM\'-\'dd\'T\'HH\':\'mm\':\'ss 2011-06-14T04:12:36

Answer 1

[T] is time designator for ISO 8601 format of T.