There's an art to debugging with print statements. You need to show enough to be able to identify problems happening, without being so verbose as to overwhelm with useless noise. When #LMDB is built with debug logging enabled, the output can be too voluminous to sift thru.

But it shows exactly what the code is doing, in such a way that you can parse the log and rerun the exact same operations, and get an identical database as a result.