Why is the Candoia aspera described as a semi-fossorial snake?

Answer

It spends significant time burrowing under debris and leaf litter

The term semi-fossorial refers to the Viper Boa's behavior of spending a large portion of its time underneath surface cover like leaf litter and soil. Its physical anatomy, including its scooped, wedge-shaped snout and stocky body, is engineered for this ground-dwelling existence, allowing it to remain cryptic while waiting for prey.

Why is the Candoia aspera described as a semi-fossorial snake?
boaphysical characteristicviper