Apple subpoenaed Valve Software near the end of last year, it's emerged, as the company sought Steam sales data to use as ammunition in its lawsuit with Epic Games.

Epic has previously been critical of Valve's Steam store, claiming it devours a large portion of the profits made by computer games. Apple's lawyers believe this is a relevant comparison for the situation Epic is complaining about on the App Store.

Valve's lawyers are reluctant to comply with Apple's request, saying it would be difficult and time-consuming, since it's not part of the usual process to retain such information.

As PC Gamer reports, Apple wants extensive and wide-ranging information from Steam. Aside from overall revenues and profits and the number of sales outside Steam that can still be traced to the store, it requested data on all games sold in the store, including title, price and when they have been on sale, as well as any in-app purchases.

Valve points out that it has nothing to do with mobile gaming, and asks the court to deny Apple's request.

This article originally appeared on Macworld Sweden. Translation by David Price.