I've recently noticed that when I have an assembly file open, in the Feature Manager Tree when I expand the tree for the component parts, that there's a folder in the tree named "Features".
When you expand the tree section to view the details of a part, under the filename you see the mates, and then everything else is in the "Features" folder. When you expand the tree section to view the details/components within a sub assembly, you see the parts in the sub assembly, mates, and then the "Features" folder which may contain Patterns, or Derived Hole Patterns etc.
I'm not sure what I've done to activate this function, but I'm pretty sure it's only just started happening. I've been through the System Options, but can't see any reference to it. I was thinking it might be a part of the large assembly mode settings, but when I turn them all off, it still shows. We're using SW Professional, 2016 SP5.