Apple has issued a subpoena to Valve, the creators of the Steam platform, demanding that the company reveals huge amounts of commercial data on Steam sales and it's operations, according to a new court filing.

It's all part of the ongoing Apple vs. Epic lawsuit over Fortnite - late last year, Epic silently pushed an update to the game that allowed users to pay them directly for microtransactions within the game, bypassing the Apple and Google app store altogether. This goes against the terms and conditions of both app stores - both companies take a 30% cut of all transactions made through apps available through their stores. Apple, in particular, didn't take to Epic's shenanigans well.

Apple then tried to kill Epic's access to its developer platform, something that was overruled by a judge, along with the removal of Fortnite from its store. The game has been absent from iOS ever since, with Epic subsequently filing a lawsuit against Apple. That's the basics, anyway - suffice to say, it's been a public and bitter rivalry.

The subpoena that Apple has issued to Valve is based on the argument that Steam's sales data and practices are essential for them to help build its case against Epic. According to their filing, it's relevant to the case because "Valve’s digital distribution service, Steam, is the dominant digital game distributor on the PC platform and is a direct competitor to the Epic Game Store." It also reveals that, at least at the moment, Valve is refusing to play along.

 "Apple and Valve have engaged in several meet and confers, but Valve has refused to produce information responsive to Requests 2 and 32," states the filing. "Valve has admitted to Apple’s counsel that the information requested exists in the normal course of business, but Valve simply refuses to produce it in any of the formats Apple suggested." 

It's an extraordinarily brave demand, frankly. Apple is basically asking Valve to give them data on their sales, financials and competitive practices, something that, predictable, Valve does not want to do. Valve argues that, contrary to Apple's claims, the requests for data are "not narrow," and include demands for data on over 30,000 games, as well as information on every version of games sold on the platform, and gross revenues broken down individually.

Of course, Valve does not even compete in the mobile gaming space, and even if it did, isn't the only store available on the platforms it operates on, which makes it all the more extraordinary to me. It's hard to see what case Apple is trying to build here. In any case, Valve is pushing for the subpoena to be thrown out.

We'll be sure to bring any further updates to this story as we learn it.