> What if the app doing the replacement uses one font with a certain font size, and the app itself uses another font with a certain font size There's no reason

> What if the app doing the replacement uses one font with a certain font size, and the app itself uses another font with a certain font size There's no reason the platform can't allow passing of styling parameters to the second process. Restricting information flow is a means to an end (safety), not the end itself, and doesn't have to be an absolute.