very difficult to spot as the MMEL is usually not available to cross-check
For US MMEL, all are available for download at the
FAA website. Keep in mind that the operator is entitled to generate an MEL quite different from the MMEL with the proviso that relevant approval processes are met.
permits the captain to defer a specific list of defects ... the captain has the authority to sign off on the ENGINEERING requirement of the MEL item as well as the OPERATIONAL requirement.
In general this will require that the captain has had sufficient training in the relevant engineering requirements to be issued with a Maintenance Authority to cover that activity.