The filing is with the US FCC, as spotted by The Walkman Blog, and while it doesn't go into extensive detail there are some interesting bits of information about Sony's 2025 flagship over-ears. The WH-1000XM6 is described in the filing as a Wireless Noise Canceling Stereo Headset and it comes with the same battery voltage as the current model – although that doesn't necessarily mean the same amount of play time,

The Sony WH-1000XM5 headphones, regarded as some of the best wireless headphones on the market, were launched three years ago in May 2022.

They seem to be slightly redesigned. Sony launched the WH-1000XM5 (such a lovely name, isn't it?) over-the-ear noise canceling headphones back in May

It’s been three long years since Sony launched its flagship WH-1000XM5 headphones, our pick for the best wireless headphones for most people, so we’re due a follow-up — and a regulatory filing indicates that the XM6 cans might nearly be ready to launch.