wp-includes/SimplePie/src/Parse/Date.php:53Date Parser
$datestringpublic$dayarraypublic$montharraypublic$timezonearraypublic$day_pcrestringpublic$month_pcrestringpublic$built_inarraypublic$userarraypublicclass Date{ /** * Input data * * @access protected * @var string */ public $date; /** * List of days, calendar day name => ordinal day number in the week * * @access protected * @var array */ public $day = [ // English 'mon' => 1, 'monday' => 1, 'tue' => 2, 'tuesday' => 2, 'wed' => 3, 'wednesday' => 3, 'thu' => 4, 'thursday' => 4, 'fri' => 5, 'friday' => 5, 'sat' => 6, 'saturday' => 6, 'sun' => 7, 'sunday' => 7, // Dutch 'maandag' => 1, 'dinsdag' => 2, 'woensdag' => 3, 'donderdag' => 4, 'vrijdag' => 5, 'zaterdag' => 6, 'zondag' => 7, // French 'lundi' => 1, 'mardi' => 2, 'mercredi' => 3, 'jeudi' => 4, 'vendredi' => 5, 'samedi' => 6, 'dimanche' => 7, // German 'montag' => 1, 'mo' => 1, 'dienstag' => 2, 'di' => 2, 'mittwoch' => 3, 'mi' => 3, 'donnerstag' => 4, 'do' => 4, 'freitag' => 5, 'fr' => 5, 'samstag' => 6, 'sa' => 6, 'sonnabend' => 6, // AFAIK no short form for sonnabend 'so' => 7, 'sonntag' => 7, // Italian 'lunedì' => 1, 'martedì' => 2, 'mercoledì' => 3, 'giovedì' => 4, 'venerdì' => 5, 'sabato' => 6, 'domenica' => 7, // Spanish 'lunes' => 1, 'martes' => 2, 'miércoles' => 3, 'jueves' => 4, 'viernes' => 5, 'sábado' => 6,Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/SimplePie/src/Parse/Date.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.