It’s the Light Switch in collapsed view or the Settings section in the expanded view.
That’s what I thought. I have a ton (50) plugins currently running on the site. There must be a limit of how many different settings are shown in the pop-out menu. The very top setting is “Writing”.
ETA: I disabled a plugin and the General tab showed back up. Looks like you can only display 31 links in the settings pop-out menu.
Even with the menu expanded? It should show up then.
Ah yes I see that it does–good to know.