Function: Callback for `wp_kses_normalize_entities()` regular expression.

Function: Determines if a Unicode codepoint is valid.

Function: Converts all numeric HTML entities to their named counterparts.

Function: Finds all attributes of an HTML element.

Function: Builds an attribute list from string containing attributes.

Function: Performs different checks for attribute values.

Function: Sanitizes a string and removed disallowed URL protocols.

Function: Removes any invalid control characters in a text string.