trying to understand my own (very old) vim macros

hello list!

I'm trying to understand the vim macros I wrote with the valuable help
from YOU (perhaps your parents :-) some 10 years ago.

there are a lot of mappings where the rhs is backslash-tilde-letter,
for example:

map \~O :let @z='q.pck'<c-M>\~W

and those mappings are then used by other mappings (just as this map
uses \~W);

what does the \~ combination mean?
is it possible to activate such mappings from the keyboard? which keys
should I type?

TIA!

--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php