@retrotechtive I think someone (@mac84tv maybe?) had a video about that. It may be an accelerator board or a video dual-screen thing for using an external monitor together with the internal one.
Following it, it leads to this unexpected extra board. Anyone know what it is? (I don't!)
It looks like this will also prevent the logic board from just sliding out, so I'll have to disassemble the entire machine to get the chassis out first.
Now, I wasn't going to show this until I'd at least attempted to make a video for it.
It's a newly arrived broken #Macintosh Plus from eBay, some of you might have even seen it on there - not very expensive but not working. I couldn't just leave it sitting there in distress so snapped it up.
However, now it's arrived, it appears this one might be a little bit special...