frameset-properties
frameset-properties is a compiled Lisp function in `frameset.el
'.
(frameset-properties FRAMESET)
This function has a compiler macro `frameset-properties--cmacro'.
Return the property list of FRAMESET.
This list is useful to store both frameset-specific and user-defined
serializable data. The simplest way to access and modify it is
through `frameset-prop' (which see).