Y'all know this...
What do you think if there were no socket markings on that top end panel? There'd be a little diagram on the baseplate, but no white panel extension down the back.
It's pretty obvious what's going on there, yes? DC in socket looks familiar, pedals usually go right-to-left for input and output, and there's a minijack'd Igor... which fits in the 3.5mm socket....
Once you know how it goes you're all set, right?
Thinking about the practicalities of labeling.
Would have a tasty dome badge logo...