For most developers using butler we recommend avoiding packaging your game into a single file before uploading it. This is because butler needs to access all your game's files in order to generate patches correctly.
Sometimes, though, your entire project actually is a single file, and it doesn't make sense for butler to wrap it in an archive. With the recently added single file support, if you upload a directory that contains just a single file we won't wrap it in an archive. Anyone downloading it from the website will get the original file.