When run from a terminal, the following message gives a clue:
user-open error: Supplied URL scheme "steam" is not allowed
The xdg-open wrapper in snapd white-lists known URL schemes (https://github.com/snapcore/snapd/blob/master/userd/launcher.go#L60), and "steam" is not one of them.
When run from a terminal, the following message gives a clue:
user-open error: Supplied URL scheme "steam" is not allowed
The xdg-open wrapper in snapd white-lists known URL schemes (https:/ /github. com/snapcore/ snapd/blob/ master/ userd/launcher. go#L60), and "steam" is not one of them.