The error maddening.error

internal: a check on MIME’s own construction, which no supported script should reach: a MIME defect, to report with the file the error names; or an error MIME raised with no code yet (error.uncoded), keeping its own class, to report so that it gets one.

MIME gives it where its code is passed by name, so its words are read where it is raised.

Reading an error and reaching its full traceback: reading an error. Every code: the index.