The implications of a judgment in favor of Oracle were staggering. Any codebase that is extensively dependent on a proprietary API is legally locked in to using that company's proprietary implementation as long as that company asserts copyright on its API. Anyone who implements the same API to offer a drop-in alternative to the proprietary product is infringing -- even if a someone privately reimplements the API without distributing the reimplementation.
Which immediately implicates WINE (Windows), Mono (.NET), ReactOS (Windows), Darling (macOS/Darwin), GNUStep (Cocoa/OpenStep), Anbox (Android), Ruffle (flash), GNU Octave (MATLAB), Mesa 3D (Direct3D), ZLUDA (CUDA), and DXVK (Direct3D 9/10/11), to name a few of the most popular...