undo-extra-outer-limit

undo-extra-outer-limit is a variable defined in `simple.el'.
Its value is

nil

• Automatically becomes buffer-local when set.

Documentation:
If non-nil, an extra level of size that's ok in an undo item.
We don't ask the user about truncating the undo list until the
current item gets bigger than this amount.

This variable only matters if `undo-ask-before-discard' is non-nil.