The forthcoming Steam Deck handheld gaming PC has just been on a healthy diet when it comes to its operating system. First posted on the Metacouncil websiteearlier this month by forum user 'I see you', a screengrab of SteamOS image 20211120.2 refers to the shirnkage.
Amongst notes on touchscreen reliability, HDMI connectivity and WiFi improvements, one point reads, "OS and pre-installed software now takes up substantially less of the internal disk space (~10GiB, down from ~24GiB)".
Pre-release speculation had the OS filling up to 40GB, presumably based on a new Windows installation for PCs of around 30GB, with Android for mobile taking between 7-32GB, depending on handset manufacturer and spec. Running on Linux-based software, we'd expected the Steam Deck OS to come in at just around 13GB, but those clever bods at Valve have obviously been busy streamlining the software for its dedicated portable hardware.
As the OP referred to in the title of their post, the reduction to just 10GB is good news for potential owners of the lowest spec 64GB edition, freeing up more space for those all-important games when every bit of storage could be critical to the hardware being a viable option for larger AAA titles.
The Steam Deck is scheduled to launch in February 2022, pushed back from December this year.