It's a mix, because some stuff tends to just use `T`, but there's better descriptors elsewhere.

There's IList<T> but Task<TResult>

There's Action<T1, T2, T3, T4, T5, T6> but also Dictionary<TKey, TValue> and Map<TIn, TOut>

This stuff kind of "makes sense" once you're used to it, because it's difficult to say what IList<T> ought to have been called otherwise, IList<TContainee> is a mouthful, and Action<T1,...> simply suffers from the inability to specify an unknown number of generic parameters.

https://learn.microsoft.com/en-us/dotnet/api/system.collecti...

https://learn.microsoft.com/en-us/dotnet/api/system.action-2...

https://learn.microsoft.com/en-us/dotnet/api/system.collecti...