This has been proposed as a W' gauge, but since I know TP is thinking of importing the dFRC chart from wko5 to TP online, it would be great if that could also be translated into a metric (imperfect though it may be) to track on TPv. Sauce for Zwift has had one for years as a gauge, so I imagine it wouldn't be too difficult to implement in some fashion. One easy improvement on the Sauce model would be to allow the user to set their FRC/W' rather than defaulting to 20 kJ.