Function: Tests if the supplied date is valid for the Gregorian calendar.

Function: Loads the auth check for monitoring whether the user is still logged in.

Function: Outputs the HTML that shows the wp-login dialog when the user is no longer logged in.

Function: Sends a HTTP header to disable content type sniffing in browsers which support it.

Function: Finds hierarchy loops using a callback function that maps object IDs to parent IDs.

Function: Uses the “The Tortoise and the Hare” algorithm to detect loops.

Function: Sends a HTTP header to limit rendering of pages to same origin iframes.

Function: Returns a comma-separated string or array of functions that have been called to get to the current point in code.

Function: Retrieves IDs that are not already present in the cache.