class Ligature_bracket_engraver;
class Ligature_engraver;
class Lily_lexer;
+class Lilypond_context_key;
+class Lilypond_grob_key;
class Line_group_engraver_group;
class Lookup;
class Lyric_combine_music;
class Music_wrapper_iterator;
class Note_performer;
class Output_def;
-class Output_def;
-class Output_def;
+class Object_key;
class Output_property;
class Page;
class Paper_book;