The blocks followed a series of reports—first about Facebook, then about Google—that showed the companies abusing the Apple Developer Enterprise Program. The program allows the installation of apps that don’t feature on the regular App Store, which is useful to developers who want to test apps before launching them, or to offer employee-only internal apps.
Facebook and Google used the mechanism to get regular people to install apps in the name of market research and in exchange for money. This allowed them to get very deep access into those users’ phones so they could monitor what they did on their handsets in close detail.
After being exposed by reports in the tech publication TechCrunch, both Facebook and Google pulled the iOS apps. However, Apple still retaliated by invalidating their enterprise certificates on Wednesday and Thursday, effectively breaking all their internal apps on the iOS platform—whether they were used for testing purposes or—say—for providing employees with bus schedules.
The move led some to note that Apple had suddenly become the U.S.’s most effective privacy regulator, but it didn’t last long.
What brought on the cessation of hostilities? That’s not quite clear—Fortune has asked Apple to elaborate, and will update this story if and when a reply rolls in.