The Steam client beta update adds preliminary support for Vulkan games, adds libvulkan aand the Vulkan ICD loader to the Steam Linux Runtime, has a few bug fixes, increases friction when using drag scrolling, and has a number of SteamVR updates.
With the Steam Controller work, the on-screen keyboard is now available from the standard desktop mode (rather than only Big Picture mode), improved stability and placement of the on-screen keyboard, and there is now support for using other controllers alongside the Steam Controller. Games with XInput support will utilize whatever controller is active.
With the initial Vulkan support and Steam Controller improvements (particularly for better supporting controllers alongside the Steam Controller), today's update is rather noteworthy. More details via SteamCommunity.com.