The WorkspaceGroup class in defined as CONST, which means that, strictly speaking, is inaccessible from outside the file workspaceAnimation.js. But Desktop Icons NG needs access to it.
Although the current Javascript engine "tolerates" this access, a warning message is shown in the log advertising that it's incorrect, and that although it is still allowed, the code should be fixed.
This patch changes the definition from CONST to VAR to allow accessing it from extensions.