Retrieve a list of protocols to allow in HTML attributes.

Extract a slice of an array, given a list of keys.

Check whether a user is still logged in, for the heartbeat.

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

Load the auth check for monitoring whether the user is still logged in.

Gets last changed date for the specified cache group.

Retrieve the file type from the file name.

Attempt to determine the real file type of a file.

Checks that a JSONP callback is a valid JavaScript callback name.

Test if the supplied date is valid for the Gregorian calendar.