(voltaOnThisStaff ,boolean?
"Normally, volta brackets are put only on the
-topmost staff. Setting this variable will create a bracket on
-this staff as well.")
+topmost staff. This variable overrides this behavior, when set to
+@code{#t} or @code{#f}.")
(voltaSpannerDuration ,ly:moment? "This specifies the maximum duration
to use for the brackets printed for @code{\\alternative}. This can be