(grob-property-description 'arch-width number? "width of the hook of a system brace.")
(grob-property-description 'arithmetic-basicspace number? "see @ref{spacing-spanner-interface}.")
(grob-property-description 'arithmetic-multiplier number? "see @ref{spacing-spanner-interface}.")
+(grob-property-description 'arpeggio-type symbol? "Type of arpeggio.
+up: a squiggly line with upward arrow,
+down: a squiggly line with upward arrow,
+bracket: a square bracket,
+plain: a plain squiggly line (default)")
(grob-property-description 'attachment pair? "cons of symbols, '(LEFT-TYPE . RIGHT-TYPE), where both types may be alongside-stem, stem, head or loose-end.")
(grob-property-description 'stem-attachment-function procedure? "Where