Did you try “man gsad” on your system to get the man page for the gsad installed on your system, explaining the available options? If you need to find the source code of gsad, you find all on gitub, which is also linked above. Be sure to check your gsad version to get to the right branch in the source code.
I guess that if you use .rpm’s from anywhere and not from the provider of your linux distribution, as your post seems to suggest, then you run indeed an integration (of OpenVAS into the system you use) not coordinated by anyone but yourself.
Otherwise, you can seach for such terminology with the magnifier glass up right on the forum pages. One relevant link would be:
which explains some of the background and risks and alternatives as well.