What it is

Knox Key Chain

Allows apps to sign data using system-wide private key/certificate pairs.

So, even though the Android Keystore provides per-app access to credentials, the Android KeyChain runs as a system user,

and hence, credentials stored through the Android KeyChain are associated with the system ID instead of a user ID.

https://docs.samsungknox.com/dev/knox-sdk/about-keystores.htm

This is only useful for apps using the TIMA Keystore. The big question I'm trying to answer is:

Which are using this except Samsung apps? Can an android dev help on this?

This package does not come off. It is part of the system core, and removing it leaves the device unusable or stuck in a boot loop. It is listed so you can recognise it, not so you can touch it.

This is not the directory. Here we say what a package is in general; what happens on your particular television is on your model's entry, and that one wins. The same package can be dead weight on one set and hold the home screen up on another.