The "default_page_template_title" filter can be used to change the title of the default page template in WordPress. It was introduced in version 4.1.
When the 'default_page_template_title' filter is called, it is passed two parameters: the label which is the display value for the default page template title, and the context where the option label is displayed.
function filter_function_name( $label, $context ) { return __( 'Custom Page Template Title', 'textdomain' ); } add_filter( 'default_page_template_title', 'filter_function_name', 10, 2 );
Where 'filter_function_name' is the function WordPress should call when filter is run.
filter_function_name should be unique function name. It cannot match any other function name already declared.