Hello @noir-Z, the (Runtime) and (Native) markings on Arch are part of Arch's distro-specific modifications of the Steam package and not part up Valve's upstream packaging. This can not be fixed from Valve's side.
Report this issue to your distro's package maintainer(s) for Steam.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
When I run Steam (Runtime) the title of the Steam window is Steam (Native) instead of Steam (Runtime).
This causes an issue with Plasma's Icons-only Task Manager in the Taskbar:
I have Steam (Runtime) pinned and due to the window being labeled Steam (Native) instead of Steam (Runtime) it won't stack on top of the pinned entry.
Steps for reproducing this issue: