Using WordPress ‘extra_{$context}_headers’ PHP filter

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The extra_{$context}_headers WordPress PHP filter allows you to add extra file headers based on a specific context.

Usage

add_filter('extra_{$context}_headers', 'my_custom_headers');

function my_custom_headers($extra_context_headers) {
    // Your custom code here
    return $extra_context_headers;
}

Parameters

  • $extra_context_headers (array): An array of extra headers for the given context. Empty array by default.

More information

See WordPress Developer Resources: extra_{$context}_headers

Examples

Add extra headers for theme

Add custom headers to the theme’s style.css file:

add_filter('extra_theme_headers', 'my_custom_theme_headers');

function my_custom_theme_headers($extra_headers) {
    $extra_headers[] = 'Theme Version';
    return $extra_headers;
}

Add extra headers for plugin

Add custom headers to a plugin’s main file:

add_filter('extra_plugin_headers', 'my_custom_plugin_headers');

function my_custom_plugin_headers($extra_headers) {
    $extra_headers[] = 'Plugin Version';
    return $extra_headers;
}

Add multiple extra headers for theme

Add multiple custom headers to the theme’s style.css file:

add_filter('extra_theme_headers', 'my_multiple_custom_theme_headers');

function my_multiple_custom_theme_headers($extra_headers) {
    $extra_headers[] = 'Theme Version';
    $extra_headers[] = 'Theme Author';
    return $extra_headers;
}

Add multiple extra headers for plugin

Add multiple custom headers to a plugin’s main file:

add_filter('extra_plugin_headers', 'my_multiple_custom_plugin_headers');

function my_multiple_custom_plugin_headers($extra_headers) {
    $extra_headers[] = 'Plugin Version';
    $extra_headers[] = 'Plugin Author';
    return $extra_headers;
}

Add conditional extra headers for theme

Add custom headers to the theme’s style.css file, but only for a specific theme:

add_filter('extra_theme_headers', 'my_conditional_custom_theme_headers');

function my_conditional_custom_theme_headers($extra_headers) {
    $theme = wp_get_theme();

    if ($theme->get('Name') == 'My Custom Theme') {
        $extra_headers[] = 'Theme Version';
    }

    return $extra_headers;
}