Thanks for the feedback. “Download” makes sense to me regardless of whether it came from a server because the end result is the same. For me the file ends up in my Downloads folders.
Just like the TW Download saver can work even if the tiddlywiki file was loaded from a file url. The browser treats it the same as any other downloaded file.
“Transfer to Filesystem” is ok for the OPFS case, but I think I’d like “Export” instead of “Transfer” in that case. However, I’m currently displaying the same “Download” buttons for the NativeFS files (i.e. browser external) in which case the files are already on the filesystem.
And using the term “Download” probably makes this worse in your eyes. I agree the storage situation needs to be made clear and I’m not sure the best way yet. I’m not convinced enough yet to avoid the term “Download”.