Hardware Homebrew How does RVLoader achieve the ability to run title without disk drive?

[Ysecond]

I searched the forum but couldn't find the answer. If you know, please ,How does RVLoader achieve the ability to run title without disc drive? Can it also work on vwii? Is there any other way to run title without disk drive?
For me, this is the last piece of puzzle of Wiiu: vwii can work normally without an disc drive, so I really want to know.