private void clearDomainObj() {
		if (domainFile instanceof GhidraFile) {
			GhidraFile file = (GhidraFile) domainFile;
			file.clearDomainObj();
		}
		else if (domainFile instanceof DomainFileProxy) {
			DomainFileProxy df = (DomainFileProxy) domainFile;
			df.clearDomainObj();
		}
	}
Returns the hidden user-filesystem associated with this objects domain file, or null if
unknown.

@return user data file system
Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapter.java