I'll look into it but my previous attempt at Butler were a failure.
There were supported options!
But it's cold out there in the real world, and on an open platform, life happens, and they stray from The Good Workflow. Nevertheless, the app tries its best to get anything it can to run, within certain rules. TL;DR: if you cannot use butler, just upload a .zip.
I've downloaded several games through the app with more than 1GB. Including one that was over 20GB.