Let’s say, for compatibility reasons, you can’t completely remove the jQuery Migrate script from your beautiful WordPress theme, and so far, everything is fine.

But seeing the warning in the console info all the time, that’s it, thank you, but no, thanks.
Four lines of code, and you’ll never see it again, regardless.

/**
 * Remove the very annoying jQuery Migrate notice.
 */
function wporg_remove_jquery_migrate_notice() {
   $m                    = $GLOBALS['wp_scripts']->registered['jquery-migrate'];
   $m->extra['before'][] = 'wporg_logconsole = window.console.log; window.console.log=null;';
   $m->extra['after'][]  = 'window.console.log=wporg_logconsole;';
}

add_action( 'init', 'wporg_remove_jquery_migrate_notice', 5 );