src/vs/workbench/api/common/extHostStoragePaths.ts/ExtensionStoragePaths/workspaceValue
class ExtensionStoragePaths:	workspaceValue(extension: IExtensionDescription): URI | undefined {
		if (this._value) {
			return URI.joinPath(this._value, extension.identifier.value);
		}
		return undefined;
	}