How do you map Command/Apple option in vim

Question

I am going through this document and this is what I gathered.

        <Esc>                Escape key
        <C-G>                CTRL-G
        <Up>                 cursor up key
        <C-LeftMouse>        Control- left mouse click
        <S-F11>              Shifted function key 11
        <M-a>                Meta- a  ('a' with bit 8 set)
        <M-A>                Meta- A  ('A' with bit 8 set)
        <t_kd>               "kd" termcap entry (cursor down key)

However I don't see how I can map Command/Apple key here. I am using plugin mentioned here. It works great. I open a tab and then I hit Command-R and I get the list of files. I could not find where the mapping is done between Command-R and the function. I am using vim settings as mentioned here

Answer 1

the modifier "D" stands for the "Command" key