To clarify format of extended arg listings: 1st column is the number of instances of EXTENDED_ARG being emitted, 2nd column is length of bytecode, followed by filename The previous numbers were of modules, which generally are run-once and listing many constants. I've attached a modification where instead I iterated over the code objects inside co_consts from compiling the *.py file. Trunk currently only emits EXTENDED_ARGs for classes (Pdb, & then the rest in Lib/typing.py) so I've omitted it