I have found a bug with Renoise’s drag and drop file loading. If you drag multiple files onto Renoise, such that at least one is a valid audio file, it will also load the last file in your selection without checking its type. This lets you load any file as raw audio data.
I just remembered that Renoise has settings for raw audio, but there’s no other way I have found to import it. I’d personally like to see it fixed so that Renoise loads any dragged files according to those settings, without having to be tricked into it.
I never thought of tricking Renoise into loading any files as raw audio, interesting. The way I have been doing this is to insert a sample slot in the list, right-click to load a sample, at the popup window, open the “Filetypes” menu, select “Show all files”, load a file, any file.