For many months now Valve has been working to improve its shader (pre-)caching support to speed-up game load times and providing a smoother gaming experience for games otherwise compiling shaders on-demand. With the Steam Deck public release quickly approaching, they continue to better that Steam pre-caching support.
With Thursday's Steam client beta update, they have made improvements to the performance and lower disk I/O when updating Mesa caches on Linux. This presumably goes along with recent upstream Mesa improvements around its handling of shader cache files.
Beyond the Mesa-specific performance and disk I/O optimizations, Steam's shader pre-caching in general should see lower memory use while processing these shader caches.
Also notable with tonight's update on the Linux side is the scout and heavy run-times seeing better compatibility with recent Let's Encrypt TLS/SSL certificate chains.
Outside of Linux-specific work, Steam Deck glyphs have been added to the Steam Input API, Steam Input now better handles offline mode, Steam Cloud should see much lower pre/post-game sync times for applications with large numbers of local files under management, and a variety of other fixes.
More details on the Steam client beta update via SteamCommunity.com .