I'm kind of surprised this isn't a topic yet. Or if not just Bubbles' chassis, the AI chassis in general.
Bubbles has synthetic skin, muscle, and hair. Her skin covers the joints in her hands, wrists, elbows, knees, ankles and feet, but it doesn't cover the seam at the base of her neck. The neck seam appears to serve as cooling ventilation. She's got individual fingers, but only 3 toe analogs that don't have seperate extentions in the skin. Bubbles has an olfactory system tuned to detect chemical and biological weapons. A
Whether or not Bubbles has a hip or shoulder seams is another question. The leotard she wears prevents us from answering a few questions directly, but there are things we can infer. We can see what appears to be hip joint seams in #3475. Her shoulders look to be different, though. Looking the muscle grouping of her shoulders, I'd actually be willing to wager that she doesn't have a seam in her shoulder like many of the other AIs we see. Which would make h the only AI we've seen who synthetic muscles extend all the way through her shoulder joints. Which means if one of her arms gets severely damaged, she has to have surgery and can't merely swap it out. We can also infer that she doesn't have a waist seam either thanks to her muscles.
So, after all of that, if she ever takes of the leotard, would she want to wear a sports bra to keep things in place when doing extensive physical work?
That question popped into my head when I was waking up today for whatever reason.