It means that before, during installation or configuration, you selected a
complete rustup profile, which pulls in not only necessary basics (like
std) and commonly used tools (like
clippy), but also something that is rarely necessary in real work (like sources of
rustc itself). In general, it should be no problem to use
default profile (by executing
rustup set profile default) and install any components not included in it separately. However, if there's only a warning and no errors, looks like your installation had succeeded.