RapidWeaver's folder structure is to name place all the resources for a page into a folder called "files". However if two pages share the same folder (such as when you change the folder of a page to "/" in the General settings sidebar) then the name of the page will be prepended to files, so you get: "indexfiles" or "page2_files" etc.
You can avoid ever getting the prepended name by ensuring that all pages are exported to their own folder. That's the default, so simply by doing nothing you'll never see the prepended name. But if you do move pages to the same folder, they do this to avoid naming collisions, so it's pretty unavoidable.
This is just how RapidWeaver names the directories. All page styles work the same within RapidWeaver. Plugins, themes, and stacks have no influence over this naming convention.