WordPress at a glance
filter is not described

list_cats filter-hook . WP 1.2.0

Filters a taxonomy drop-down display element.

A variety of taxonomy drop-down display elements can be modified just prior to display via this filter. Filterable arguments include 'show_option_none', 'show_option_all', and various forms of the term name.

Usage

add_filter( 'list_cats', 'filter_function_name_7285', 10, 2 );
function filter_function_name_7285( $element, $category ){
	// filter...

	return $element;
}
$element(string)
Category name.
$category(WP_Term/null)
The category object, or null if there's no corresponding category.

Where the hook is called

wp_dropdown_categories()
list_cats
Walker_Category::start_el()
list_cats
Walker_CategoryDropdown::start_el()
list_cats
wp-includes/category-template.php 414
$show_option_none = apply_filters( 'list_cats', $r['show_option_none'], null );
wp-includes/category-template.php 423
$show_option_all = apply_filters( 'list_cats', $r['show_option_all'], null );
wp-includes/category-template.php 431
$show_option_none = apply_filters( 'list_cats', $r['show_option_none'], null );
wp-includes/class-walker-category.php 100-104
$cat_name = apply_filters(
	'list_cats',
	esc_attr( $category->name ),
	$category
);
wp-includes/class-walker-category-dropdown.php 61
$cat_name = apply_filters( 'list_cats', $category->name, $category );

Where the hook is used (in WP core)

wp-includes/default-filters.php 200
add_filter( 'list_cats', 'wptexturize' );