你要找的钩子是wp_head.

功能。php

add_action( \'wp_head\', \'se343581_add_preload_tag\', 5);
function se343581_add_preload_tag()
{
    echo \'<link rel="preload" href="\'. 
         plugins_url(\'/gdpr-cookie-compliance/dist/styles/lity.css\') .
         \'" as="style">\';
    //
    // -- if added in plugin file --
    // echo \'<link rel="preload" href="\' . plugin_dir_url( __FILE__ ) . \'some_subdir/file_name.css" as="style">\';
}