[MediaMole]

Reading into that, it is a test of the blast effect and fallout from a sub-kiloton, deep penetration nuclear bunker buster.

[Skywarner]

"Reading into that, it is a test of the blast effect and fallout from a sub-kiloton, deep penetration nuclear bunker buster."

Bingo.

[thackney]

Yep, I read this a just a confirmation to confirm the calculation method. Not an test of the explosive, but the effects of that size of "bunker buster". The actually usage might be a strategic nuke that penetrates before the reaction.