Having trouble understanding part of `'runtimepath'` documentation

Question

I get the basics of the runtimepath as explained in :h 'runtimepath'. Except for the remark at the end

for Neovim (nearly identical in Vim):

    You can put a directory before $VIMRUNTIME to find files which replace
    distributed runtime files.  You can put a directory after $VIMRUNTIME
    to find files which add to distributed runtime files.

What I don't understand is the sense in which putting a directory before $VIMRUNTIME replaces distributed runtime files. I thought that putting something before in $RUNTIMEPATH just affects the order in which its contents are sourced/loaded.

So could this just be poor phrasing in the documentation or am I missing something?

And in this case, I interpret 'distributed' as meaning 'coming packaged with vim when you installed it' instead of the sense of 'distributed computing' or 'distributed version control'.

Answer 1

It does affect order loaded; but, most of $VIMRUNTIME files check certain "did_X" guards and bail out. So if earlier files set those flags, $VIMRUNTIME files skip themselves.