So I effed up. I was editing '/etc/config/dhcp', that is, swapping it out for another one that I had sorted, and now the menu item 'Network' -> 'DHCP and DNS' has disappeared. Is there any way to repair this? Swapping the config file back does not do the trick.
Well, I might have to try that. But is there not a less drastic way of repairing this? And what exactly happened? I have done this sort of thing before, without issues.
That did the trick. I must have read through that file 5 times, and somehow missed the 'onfig host' on line 146 every time. 'uci show dhcp' told me where to look for my error. Thank you for taking the time to save me from myself.