Many may think that EDIFACT is easy to parse, which may be the case. But it is NOT easy to interpret.

There are hundreds of "substandards" per industry. For example for clothes or medicine, most vendors have custom fields outside of the standard which MUST be interpreted/sent or everything falls apart

In my corner of the world, all official grammar descriptions finish with a sentence like "or another interpretation by bilateral agreement" (where bilateral means between any two vendors using the same "standard").