WordPress at a glance
filter is not described

wp_default_editor filter-hook . WP 2.5.0

Filters which editor should be displayed by default.

Usage

add_filter( 'wp_default_editor', 'filter_function_name_9200' );
function filter_function_name_9200( $r ){
	// filter...

	return $r;
}
$r(string)
Which editor should be displayed by default. Either 'tinymce', 'html', or 'test'.

Where the hook is called

wp_default_editor()
wp_default_editor
wp-includes/general-template.php 3091
return apply_filters( 'wp_default_editor', $r );

Where the hook is used (in WP core)

Does not used.