Apple Service Document: 2018 MacBook Pro Keyboard Membrane to Prevent Debris From Entering Butterfly Mechanism 

A new Apple service document outlines changes to the new MacBook Pro keyboard. Text from the document was provided to MacRumors:

The keyboard has a membrane under the keycaps to prevent debris from entering the butterfly mechanism. Be careful not to tear the membrane. A torn membrane will result in a top case replacement.

This is good news; I hope that it works as intended.

The document also states that it is now much easier to replace individual key caps, and that full top case replacements should be less common now. If a key is stuck, feels uneven or soft, a technician should be able to safely remove and even replace it in store now. That wasn’t the case before, which blows my mind.

John Gruber:

This is what I thought all along: the new third-generation keyboard was designed to better in every way, quieter and more durable, but Apple, for legal and/or marketing reasons, has decided only to tout that the new design is quieter.