No way to get the armor, mainhand or offhand inventory

Steps to Reproduce:

1. create addon featuring GameTest code
2. Retrieve an entity
3. Find a component that allows access to the armor inventory ("minecraft:armor"?), mainhand ("minecraft:mainhand"?) or offhand ("minecraft:offhand"?)

Observed Results:
No such components exist.

Expected Results:
The components exist and are accessible like an actual inventory, much like "minecraft:inventory".