At the moment, the documentation on IsA, FindFirstAncestorWhichIsA, and FindFirstChildWhichIsA and all of the API pages reference Instance inheritance. This inheritance is not documented anywhere in the wiki. The closest any page comes to this is the page on IsA which mentions type introspection but fails to link any resources on inheritance in Roblox.
There should be a page on class inheritance. It should explain it more thoroughly and either include or link to a map of inherited classes. That map should be kept up to date and be based on the API alone. The existing class tree is not a viable replacement for this because it is not accurate to the API dump. At the very least, it does not list the various Value classes as inheriting from ValueBase, which puts the entire tree into question.
There should also be some indicator of what classes something inherits from on their API pages. This would be helpful to quickly identify the base classes of something without using the API map – as it stands, there is no way to know what something inherits from without looking at the API dump, which defeats the entire purpose of the developer hub. On the older wiki (sorry, I know this is a bad thing to say), that inheritance of a class was readily available and it was helpful as a power user.
Inheritance is a fundamental part of Roblox’s API and it should be documented somewhere on the developer hub.