At 5:12 he showed what the menu should be like from an old screenshot, which has a multiplayer button (right bottom, "two computer double arrow to each other",

At 5:12 he showed what the menu should be like from an old screenshot, which has a multiplayer button (right bottom, "two computer double arrow to each other", refer as B2 below). On the left of it, it's a button of "a worm with a hard hat", refer as B1 below. In his GOG copy, even after fix, there is only B1 and it's centered now to occupy the full space. At the end of the video, after the fix, he was still clicking B1 button to enter "network play" since no B2 button is there. So I'm still confused. He didn't restore the missing button. But of course he did something. Did he re-bind the networkplay dialog entrance from missing B2 to B1? What happens if you just click B1 before the fix? Was B1's original functionality overridden by his fix? Alternatively, if it's indeed supposed to be at B1 (I can't tell from icon what its functionality is), then why even mentioning the mission B2 to begin with?