PHP has had the "ERA=131116" constant since at least PHP 4.3.0 (probably longer): https://3v4l.org/XYZZ1
but what does it mean? what is it used for? get_defined_constants($categorize = true); puts it under the "standard" category, which doesn't help me much, and googling it doesn't seem to turn up anything useful, and the only documented constant i can find which sort-of looks similar is IntlCalendar::FIELD_ERA, which is a 0 (a far cry from 131116, I guess it is not related)
