Rototilt on Komatsu excavators

Komatsu excavators equipped with Rototilt attachments working in various excavating applications including a tough digging job.
Rototilt is a durable, versatile excavator and backhoe attachment. It combines side tilt, continuous rotation, and a hydraulic quick coupler in one package. The attachment can be rotated and tilted at the same time, making it simple to operate around or under obstacles and for any type of ground contouring. This unique combination of continuous rotation and side tilt lets you operate in extremely tight work areas and approach your job from any angle.
Rototilt is sold through all major excavator and backhoe dealers throughout North America.
Rototilt, the world's most popular Tiltrotator. Please subscribe to the Rototilt North America channel.

[@RototiltNorthAmerica]

I believe it was for transit system upgrades for the Vancouver Olympics

[@JUSTINJOB]

What was the purpose of this hole?