Used By	Description
wp-includes/functions.php: current_datetime()	Retrieves the current time as an object with the timezone from settings.
wp-includes/functions.php: wp_date()	Retrieves the date, in localized format.
wp-includes/general-template.php: get_post_datetime()	Retrieve post published or modified time as a `DateTimeImmutable` object instance.
wp-includes/formatting.php: get_gmt_from_date()	Returns a date in the GMT equivalent.
wp-includes/formatting.php: get_date_from_gmt()	Converts a GMT date into the correct format for the blog.
wp-includes/formatting.php: iso8601_to_datetime()	Converts an iso8601 (Ymd\TH:i:sO) date to MySQL DateTime (Y-m-d H:i:s) format used by post_date[_gmt].
wp-includes/functions.php: date_i18n()	Retrieves the date in localized format, based on a sum of Unix timestamp and timezone offset in seconds.
wp-includes/functions.php: mysql2date()	Convert given MySQL date string into a different format.
wp-includes/functions.php: current_time()	Retrieves the current time based on specified type.
wp-includes/class-wp-date-query.php: WP_Date_Query::build_mysql_datetime()	Builds a MySQL format date/time based on some query parameters.

wp_timezone

wp_timezone()