WordPress at a glance
filter is not described

mce_external_plugins filter-hook . WP 2.5.0

Filters the list of TinyMCE external plugins.

The filter takes an associative array of external plugins for TinyMCE in the form 'plugin_name' => 'url'.

The url should be absolute, and should include the js filename to be loaded. For example: 'myplugin' => 'http://mysite.com/wp-content/plugins/myfolder/mce_plugin.js'.

If the external plugin adds a button, it should be added with one of the 'mce_buttons' filters.

Usage

add_filter( 'mce_external_plugins', 'filter_function_name_5528', 10, 2 );
function filter_function_name_5528( $external_plugins, $editor_id ){
	// filter...

	return $external_plugins;
}
$external_plugins(array)
An array of external TinyMCE plugins.
$editor_id(string)
Unique editor identifier, e.g. 'content'. Accepts 'classic-block' when called from block editor's Classic block.

Changelog

Since 2.5.0 Introduced.
Since 5.3.0 The $editor_id parameter was added.

Where the hook is called

_WP_Editors::editor_settings()
mce_external_plugins
wp_tinymce_inline_scripts()
mce_external_plugins
wp-includes/class-wp-editor.php 420
$mce_external_plugins = apply_filters( 'mce_external_plugins', array(), $editor_id );
wp-includes/script-loader.php 463
$external_plugins = apply_filters( 'mce_external_plugins', array(), 'classic-block' );

Where in WP core the hook is used

Usage not found!