Origin or meaning of characters like "U\R\D\V" in GVIM tabs?

Per the attached screenshot, why do my GVIM tabs include characters such as ""U\R\D\V"?

On other occasions / files, the tabs might include "\P\M\M\F\R\F\R\T".

What are these characters?

Cheers & thanks,
sfosparky
SFO

--
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