Variable: view-return-to-alist

What to do with used windows and where to go when finished viewing buffer.
This is local in each buffer being viewed.
It is added to by `view-mode-enter' when starting to view a buffer and
subtracted from by `view-mode-exit' when finished viewing the buffer.

See RETURN-TO-ALIST argument of function `view-mode-exit' for the format of
`view-return-to-alist'.