WordPress at a glance
filter is not described

list_pages filter-hook . WP 3.1.0

Filters the page title when creating an HTML drop-down list of pages.

Usage

add_filter( 'list_pages', 'filter_function_name_7753', 10, 2 );
function filter_function_name_7753( $title, $page ){
	// filter...

	return $title;
}
$title(string)
Page title.
$page(object)
Page data object.

Where the hook is called

Walker_PageDropdown::start_el()
wp-includes/class-walker-page-dropdown.php 82
$title = apply_filters( 'list_pages', $title, $page );

Where the hook is used (in WP core)

wp-admin/includes/admin-filters.php 158
add_filter( 'list_pages', '_wp_privacy_settings_filter_draft_page_titles', 10, 2 );