apply_filters( 'mce_buttons', array $mce_buttons, string $editor_id )

Filters the first-row list of TinyMCE buttons (Visual tab).

Parameters

$mce_buttons array: First-row list of buttons.
$editor_id string: Unique editor identifier, e.g. 'content'. Accepts 'classic-block' when called from block editor's Classic block.

See other relevant mce_buttons hooks:

File: wp-includes/class-wp-editor.php. View all references

$mce_buttons = apply_filters( 'mce_buttons', $mce_buttons, $editor_id );

Used By
Used By	Description
wp_tinymce_inline_scripts() wp-includes/script-loader.php	Adds inline scripts required for the TinyMCE in the block editor.
_WP_Editors::editor_settings() wp-includes/class-wp-editor.php