Macintosh Plus side view, where the cables seem to go. What is that little board in there?

Notices where this attachment appears

1. Embed this notice
   retrotechtive (retrotechtive@retrochat.online)'s status on Friday, 01-Dec-2023 03:37:18 JST retrotechtive

   in reply to

   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.