There's something weird about the naming scheme here.
Article about X0 (Air Bud)
List of articles about X1 (Dogs playing basketball)
Lists of articles about X2 (Dogs playing sports)
List of lists of lists
Level 3 should have been "List of lists of articles". And if 4 had been fully specified as "List of lists of lists of articles about X3", it wouldn't contain itself.
They better all be mapped and crossreferenced in OSM
do I have news for you
I clicked on the Bicycle Tree and it is missing the species= and wikipedia= tags