Can these Tyco NM splices be buried in the wall?

Do the installation instructions of this splice kit specifically allow this? If not, then you cannot bury a splice in a wall in accordance with the electrical code...
This is not a good practice to begin with as most of us have searched for a splice that has gone bad only to find that is was buried in a wall somewhere.
What would you need to do to splice this in box?

The Code, Section 334.40(B), that allows these devices to be used for exposed, or fished in existing buildings, is clear about no boxes would be needed, but not clear if this connection requires access.

I would not use these when the connection would be buried in a wall.

Reading up on the Technical specs for this connector on the TYCO website,
Yes, it is listed for and allowed to be concealed by the electrical code.
But again, I agree with TK, try to avoid burying this in a wall...