Official development documentation from Microsoft continues to reference Xbox Lockhart.
Microsoft has yet to officially announce its reportedly cheaper, less powerful next-gen console codename Lockhart. The Xbox Series X's little brother has been rumoured for a while now, and is said to be a disc-less 4TF machine.
Every few months, Microsoft updates its Gamecore Development Kit, which covers all of its currently supported Xbox platforms. The most recent update, spotted by security researcher TitleOS, openly references Lockhart as one of two performance profiles available under the Series X family of devices.
More proof of Lockhart, this time from the XDK/GDK release notes for June 2020. pic.twitter.com/hulDoC9owv
— TitleOS (@XB1_HexDecimal) June 24, 2020
Profiles typically represent targets each console could hit, and they help developers optimise their code to run on the different Xbox consoles, such as enabling/disabling certain effects to get the desired results.
Earlier this month, the same researcher spotted another reference to Lockhart in the console's OS, yet another piece of evidence in the growing list. Of course, those references do not tell us anything about the console itself. Indeed, very little is known of Lockhart outside of its performance target.
The good news is that we have to be getting closer to Lockhart's official reveal. Microsoft has a first-party event in July where we expect to see, among other things, a look at Halo Infinite gameplay. It stands to reason that Lockhart will be revealed at that event.