allout-widgets-changes-record is a variable defined in `allout-widgets.el'.
Its value is

  • Automatically becomes buffer-local when set.

Record outline changes for processing by post-command hook.

Entries on the list are lists whose first element is a symbol indicating
the change type and subsequent elements are data specific to that change
type. Specifically:

'exposure `allout-exposure-from' `allout-exposure-to' `allout-exposure-flag'

The changes are recorded in reverse order, with new values pushed
onto the front.