Also happening with latest build:

Hello @nightsky30, this may change in the future, but for now this is an intentional addition to Steam's System information to help identify driver issues and runtime variations between Linux distros.
Nothing extracted yet.
Your system information
https://gist.github.com/nightsky30/d6e5e435c7825f7c5d1570e51930cfba
Please describe your issue in as much detail as possible:
System Information dialog box is populated with duplicated raw JSON and error message at the bottom of its contents. It gets copied out as well with everything else.
Error below JSON: "The Steam Linux Runtime container tool is not Installed."
Steps for reproducing this issue: