```
function wp_is_mobile() {‌‌
if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {‌‌
$is_mobile = false;
} elseif ( strpos( $_SERVER['HTTP_USER_AGENT'], 'Mobile' ) !== false // Many mobile devices (all iPhone, iPad, etc.)
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Android' ) !== false
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Silk/' ) !== false
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Kindle' ) !== false
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'BlackBerry' ) !== false
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mini' ) !== false
|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mobi' ) !== false ) {‌‌
$is_mobile = true;
} else {‌‌
$is_mobile = false;
}

/**
* Filters whether the request should be treated as coming from a mobile device or not.
*
* @since 4.9.0
*
* @param bool $is_mobile Whether the request is from a mobile device or not.
*/
return apply_filters( 'wp_is_mobile', $is_mobile );
}
```

https://developer.wordpress.org/reference/functions/wp_is_mobile/