+A time-based footnote allows such layout objects to be annotated
+without referring to an event. The general form for Time-based
+footnotes is:
+
+@example
+\footnote [@var{mark}] @var{offset} @var{footnote} [@var{Context}].@var{GrobName}
+@end example
+
+@end table
+
+The elements for both forms are:
+
+@table @var
+
+@item direction
+If (and only if) the @code{\footnote} is being applied to a
+post-event or articulation, it must be preceded with a direction
+indicator (@code{-, _, ^}) in order to attach @var{music} (with
+a footnote mark) to the preceding note or rest.
+
+@item mark
+is a markup or string specifying the footnote mark which is used for
+marking both the reference point and the footnote itself at the
+bottom of the page. It may be omitted (or equivalently replaced with
+@code{\default}) in which case a number in sequence will be generated
+automatically. Such numerical sequences restart on each page
+containing a footnote.
+
+@item offset
+is a number pair such as @samp{#(2 . 1)} specifying the X and
+Y@tie{}offsets in units of staff-spaces from the boundary of the
+object where the mark should be placed. Positive values of the
+offsets are taken from the right/top edge, negative values from the
+left/bottom edge and zero implies the mark is centered on the edge.
+
+@item Context
+is the context in which the grob being footnoted is created. It
+may be omitted if the grob is in a bottom context, e.g. a
+@code{Voice} context.
+
+@item GrobName
+specifies a type of grob to mark (like @samp{Flag}). If it is
+specified, the footnote is not attached to a music expression in
+particular, but rather to all grobs of the type specified which
+occur at that moment of musical time.
+
+@item footnote
+is the markup or string specifying the footnote text to use at the
+bottom of the page.
+
+@item music
+is the music event or post-event or articulation
+that is being annotated.
+
+@end table
+
+@subsubsubheading Event-based footnotes
+
+@cindex footnotes, event-based
+
+A footnote may be attached to a layout object directly caused
+by the event corresponding to @var{music} with the syntax:
+
+@example
+\footnote [@var{mark}] @var{offset} @var{footnote} @var{music}
+@end example
+
+@lilypond[quote,verbatim,papersize=a8landscape]