There is no opcodes.pod; I'm assuming the pointer should actually be to parrot_assembly.pod, as the canonical documentation.
Simon --- overview.pod.old Mon Jan 28 19:42:55 2002 +++ overview.pod Mon Jan 28 19:43:06 2002 @@ -65,7 +65,7 @@ These areas will roughly map to compilation units of the original source; each precompiled module will have its own opcode table. -For a closer look at Parrot ops, see L<opcodes>. +For a closer look at Parrot ops, see L<parrot_assembly>. =head1 PMCs