Okay, I'm fiddlin' with robots. There've been some changes since last I played in that sandbox.
Original robot Book 8 had weight (well, mass) for appendages but no volume; I was left to conclude that the appendages were exterior to the chassis. CT Errata says we take the weight as the volume. Do we deduct the volume of the appendages from the chassis volume (i.e. the "chassis" is considered the chassis plus appendages; perhaps the appendages store in or snug up to the chassis when not in use), or do we - as with the head - add the appendage volume to the volume of the chassis to obtain an overall volume for Mr. Roboto?
Book 8 also has weights for sensors, devices and weapons - but no volumes. There's a rule setting limits to how much weight an appendage can carry. There's a rule adding the volume of the "head" to the total chassis volume, so that at least is clearly outside the chassis. However, it's not clear what's inside it and what's attached on the outside of it. Are these various accoutrements exterior to the chassis/head/appendage? Exterior to the appendage but deducted from the chassis/head?
In other words, if I grab a janitorial tool package, does it ride in a box on the outside or get stored inside the chassis, presumably for the arms to select and use what tools they wish? If I put a basic sensor package in the chassis or head, is it inside or outside? If I slap a basic sensor package on an arm to peer around corners, is it inside or outside?
A scientist and his assistant walk into a bar.
The scientist says, "I'll have some H2O."
The assistant says, "I'll have some H2O too."
The assistant dies.