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filter is not described

sanitize_trackback_urls filter-hook . WP 3.4.0

Filters a list of trackback URLs following sanitization.

The string returned here consists of a space or carriage return-delimited list of trackback URLs.

Usage

add_filter( 'sanitize_trackback_urls', 'filter_function_name_2853', 10, 2 );
function filter_function_name_2853( $urls_to_ping, $to_ping ){
	// filter...

	return $urls_to_ping;
}
$urls_to_ping(string)
Sanitized space or carriage return separated URLs.
$to_ping(string)
Space or carriage return separated URLs before sanitization.

Where the hook is called

sanitize_trackback_urls()
sanitize_trackback_urls
wp-includes/formatting.php 4870
return apply_filters( 'sanitize_trackback_urls', $urls_to_ping, $to_ping );

Where the hook is used (in WP core)

Does not used.