Unsupported operand types in … domain_color.module

Hm array_merge overwrites while += just sets the values if it's not set on the left array.
Curious if it's failing due to $info['schemes']['default']['colors'] being NULL? In this case, we should check that it's set and that should be it...
Something like the following:

    $schemes[$key] += $info['schemes']['default']['colors'] ?? [];

Committed a slightly different patch.

Automatically closed - issue fixed for 2 weeks with no activity.