+ (parent-alignment-X ,number? "Specify on which point
+of the parent the object is aligned. The value @w{@code{-1}} means
+aligned on parent's left edge, @code{0}@tie{}on@tie{}center, and
+@code{1}@tie{}right edge, in X@tie{}direction. Other numerical
+values may also be specified - the unit is half the parent's width.
+If unset, the value from @code{self-alignment-X} property will be
+used.")
+ (parent-alignment-Y ,number? "Like @code{parent-alignment-X}
+but for the Y@tie{}axis.")
+ (parenthesis-friends ,list? "A list of Grob types, as symbols.
+When parentheses enclose a Grob that has 'parenthesis-friends, the
+parentheses widen to include any child Grobs with type among
+'parenthesis-friends.")