This section describes all the different formats that the
DateTimeImmutable, DateTime,
date_create(),
date_create_immutable(), and
strtotime() parser understands. The formats are grouped
by section. In most cases formats from different sections, separated by
whitespace, comma or dot, can be used in the same date/time string. For each
of the supported formats, one or more examples are given, as well
as a description for the format. Characters in single quotes in
the formats are case-insensitive ('t' could
be t or T), characters in
double quotes are case-sensitive ("T" is only
T).