Some players using Linux have been experiencing crashes when launching the game. This was happening when a joypad (or a keyboard/mouse that is recognized as a joypad) was connected to the computer. That shouldn't happen any more.
Now when a server attempts to open a website in a player's Steam overlay, the player will be asked for confirmation first. You should always take care when visiting websites you don't know, so allowing servers to just pop open websites was never a great idea.