The Steam client on Linux is now a 64bit application, and it runs inside a Steam Runtime container, according to the patch notes for the November 11 client update. The update downloads automatically, so Linux users will not need to do anything to receive it.
The client now runs on the same container technology that Steam games use
Valve says the Steam Runtime container is the technology games already run in, and that it will help the client provide a more consistent experience across distributions. That could make the client less dependent on the libraries a distribution happens to ship, though it is not clear which parts of the client moved into the container.
A suspend crash, a lobby crash and the updater window are fixed in the same release
The Linux section also fixes a crash when resuming from suspend and a crash when creating a lobby in games that use the ISteamNetworking interface, with Sons of the Forest as the example. The updater window, which failed to show for some users, now appears reliably and has a new look.
Remote Play can now capture HDR from a Linux desktop through PipeWire
In the Remote Play section, HDR capture now works when streaming from a Linux desktop using PipeWire, and from macOS. A new client setting for HDR offers Automatic, On and Off, and HDR is enabled again on the Steam Deck OLED. The client also gets a brightness slider in the streaming overlay and a Display Style setting for stretching or zooming a stream with a different aspect ratio.
Minimum requirements and any 32-bit library changes are missing from the release
The notes appear to give no minimum system requirements for the 64bit client, and they do not address 32-bit games or the distributions that package Steam themselves. The update also includes a second round of startup performance work, but the notes appear to give no figures, so how much faster the client launches is unknown.