Returns the regexp for common whitespace characters.

Converts a number of HTML entities into their special characters.

WordPress implementation of PHP sprintf() with filters.

Localizes list items before the rest of the content.

Converts emoji to a static img element.

Converts emoji in emails into static images.

Properly strips all HTML tags including script and style

Adds rel="noopener" to all HTML A elements that have a target.

Callback to add rel="noopener" string to HTML A element.

Generates an excerpt from the content, if needed.