I suspect this was already being attempted with the 32-bit/scout client, it's probably just become more visible because the new steamrt3c-based client launches diagnostic tools via steam-runtime-launch-client which has error logging by default.
If there's no functional impact, then this is only minor.
Nothing extracted yet.
When running a 32-bit client, there is no such error, although lsb-release was missing. When starting SteamRT3, the journal writes this error:
steam-runtime-launch-client[19409]: E: Failed to start command: Failed to execute child process "lsb_release"All modern distributions now rely on /etc/os-release, could steam work with it?
Steps for reproducing this issue: