SteamOS changes that landed today to both the "Alchemist" and "Alchemist Beta" repositories include updating the Iceweasel (Firefox-derived) web-browser to 24.3.0esr, valve-bugreporter improvements for reporting more package versions, package updates, and fixing a bug where mouse input would sometimes stop when holding a mouse button. Package updates to both repositories include Apache2, OpenSSL, TZdata, and e2fsprogs. These package updates were pulled in from the Debian stable repository as bug-fixes.
Landing in the stable package repository for SteamOS were also some earlier Alchemist beta changes.
More details at SteamCommunity.com.