I suspect that the implementation of any API would come under the shadow of this ruling. For instance, replacing a proprietary product with an open-source variant that has the same API would also be illegal or subject to licensing fees.
In my opinion, this will be bigger than proprietary languages and cover drop-in replacements for pretty much any proprietary code, thus providing yet another way to lock customers into a particular product.
In my opinion, this will be bigger than proprietary languages and cover drop-in replacements for pretty much any proprietary code, thus providing yet another way to lock customers into a particular product.