I'm encountering it too. I've not ever noticed it before and don't feel much performance loss. I deleted "DocumentationCache" and "DocumentationIndex" at least.

Excuse me for my glitchy network...

Thanks for helping. I missed something and now worked out solution for my needs.

Thanks for responding. The defaults I mentioned is about any way to access macOS preferences subsystem (.plist, including NSUserDefaults). To enable Metal HUD for apps I need to monitor, I just set MetalForceHudEnabled to YES for those apps, once. However, if I want to customize what to show in Metal HUD 4, I have to use open with MTL_HUD_ELEMENTS because I haven't found its plist key yet.