Sometimes it’s useful to do destructive testing. For example, I am building a (small) server cabinet out of a piece of Ikea furniture; specifically in this case adding ventilation to the top.
Low and behold, when drilling the vent, I discovered this:
Yes, that’s right. Cardboard on the inside. Looking at the plug I drilled out:
Sigh. Ikea really has gone downhill. 🙁