I mean, it sounds like the Red Alert code is available under GPLv3 (plus some additional "we want to be very clear, this doesn't cover the trademark" terms tacked on), but you can't build it without DX5, which gets compiled into the binary, thereby making the binary non-free. Someone could port it from DX5, GCL, and HMI and produce something that builds as GPL.
The other part is it doesn't include the game assets or usable replacements, much like OpenRA, or OpenTTD for the first half of its life.
I'm not going to fault EA too much for this approach, particularly if it paves the way to open sourcing e.g. EOL MMOs and the like if game devs don't feel the obligation to port away from all the commercial libraries. I've seen game devs who I genuinely believe on this say things to the effect of "Oh yeah, we'd totally open source dead game X, except we'd have to port it away from Bink and Havok and XYZ, and we don't have the time to do that for 0 revenue"
OpenRA doesn't ship with the assets+ for Tiberian Dawn, Red Alert, and Dune 2000 but they're downloadable straight from the UI as they were made officially available by EA/Westwood.
+ Without the music and cutscenes. If you want that you need original discs or other dematerialized versions.
That sounds reasonable, but they could have worded it differently.
They first statement about DX:
> or write new replacements (or remove the code using them entirely) for the following libraries;
But, they say that binary is proprietary regardless, no conditions. So it is very difficult to say.
If the code compiles without assets (no mention about them, it sounds like it should compile), then the resulting binary should be free to use. Missing runtime assets are different problem, and separate from the binary usage permissions.
They don't say the binaries are proprietary. "To use the compiled binaries, you must own the game." is not a statement about licensing, which is why it is not under the "license" section. It's a statement about completeness of the repository: it doesn't include the game data which you need to obtain separately buy buying the game. This is pretty much standard for open source releases of old games.
The other part is it doesn't include the game assets or usable replacements, much like OpenRA, or OpenTTD for the first half of its life.
I'm not going to fault EA too much for this approach, particularly if it paves the way to open sourcing e.g. EOL MMOs and the like if game devs don't feel the obligation to port away from all the commercial libraries. I've seen game devs who I genuinely believe on this say things to the effect of "Oh yeah, we'd totally open source dead game X, except we'd have to port it away from Bink and Havok and XYZ, and we don't have the time to do that for 0 revenue"