Module registry 

Registered custom properties.

Structs

PropertyRegistration

A computed, already-validated property registration. https://drafts.css-houdini.org/css-properties-values-api-1/#custom-property-registration

ScriptRegistry

The script registry of custom properties. https://drafts.css-houdini.org/css-properties-values-api-1/#dom-window-registeredpropertyset-slot