Edge and Chrome can enable multi-threaded downloads, but I found that Firefox doesn't have this feature, and I need to download a multi-threaded download extension to do this. But I hope that Firefox natively supports multi-threaded downloads, and if you can, you can turn it on by default, because multi-threaded downloads themselves will only bring some benefits without affecting the user experience, so just turn it on by default to avoid trouble. Also, the switch for multi-threaded downloads should be placed in the browser settings, not in about:config, otherwise even if Firefox had multi-threaded downloads, who knows? There are a lot of useful features that you don't put in your browser settings, and users just think that Firefox doesn't have them