Valve continues to push Ubuntu as the primary platform for supporting Steam on Linux. The Steam Linux binary has been a Debian/Ubuntu package while others have had no issues making the binary work on their own distribution of choice. Arch and other Linux distributions have sought re-packaging the Steam client so they can easily ship the gaming distribution platform to their users.
With an update to the Steam Linux client this week, as noted in the Steam Client Beta Group, it's now officially okay to re-package the client. One of the noted changes to this latest beta update is "Added license to allow repackaging for other Linux distributions."
The Linux client update also has a couple of fixes and the Steam Runtime has now been reduced by 50%.