A better description would be "lactase treated" milk.
In any case, I found consuming it regularly for breakfast still lead me to feel unwell over time.
However I can periodically consume dairy when I take a strong dose of lactase supplements.
From some literature it does appear that manufacturers can use "lactose free" even for non-zero amounts of lactose (10mg per 100g).
This is actually higher lactose density than many cheese varieties, especially considering I would be consuming say 150-200g of yogurt, whereas if I am eating cheese its in small careful quantity.
Its a reference to the previous comment's 'specially engineered cows' quip - these cows do exist and produce a milk that is easier to digest (but still contains lactose).
For example - lactose-free yogurt is often just regular yogurt with lactase enzyme added.
If that's what I wanted, I'd buy regular yogurt and take a lactaid supplement.