What's the differences between the kernel commands \trivlist and \list?

Question

LaTeX defines the two environments \trivlist and \list. Both can be used creating own environments.

What exactly is the differences between \trivlist and \list?

Answer 1

\list is less triv(ial) than \trivlist.

Essentially \list has hooks for setting the label format which trivlist doesn't use (as it's normally used in things like center where the label/item is hidden, or theorems where there is only one item).

It's premature optimisation in a way: @egreg had to patch a command in an answer the other day to use list not trivlist so that the formatting could be changed. Had the original used list it would have been a trivial setting.