After many struggles, I have finally located the source of where the current 5-C rating of Command Blocks and Bedrock comes from.

However, I believe that either I'm misunderstanding the calculations, or the math behind Moon Level was wrong. 

According to all of this information in the link I provided, unless I have done something wrong, the formula is "(1.3 × (1542860 / (1 × 0.75)) × 1)/1000" (the /1000 part is merely for the convenience of translating to kilometers).

The resulting number I get is 2674.29066667 kilometers of a nonnuclear explosion, which according to this page only qualifies for large country level.

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