This code is removing query string arguments from the resource URLs, javascripts and style sheets, that are denote the version of your WordPress or plugin that you are using.
A must for all WP installations
function _remove_script_version( $src ){
$parts = explode( '?ver', $src );
return $parts[0];
}
add_filter( 'script_loader_src', '_remove_script_version', 15, 1 );
add_filter( 'style_loader_src', '_remove_script_version', 15, 1 );Source: https://kinsta.com/knowledgebase/remove-query-strings-static-resources/