What lives in your fit record
Your Size Passport can hold body measurements, garment measurements, fitting notes, fit preferences, scan history, exports and access approvals. The point is to preserve useful context instead of letting it disappear into a single brand's system, which is where it currently goes.
Body measurements describe the person: chest, waist, hip, neck, sleeve, back length, shoulder width, inseam, and the postural values a tape measure does not capture — shoulder slope, back curvature, shoulder drop. Garment measurements describe the finished piece, which is a different thing and is stored separately. A body has a chest circumference; a jacket has a chest measurement that includes whatever ease the cutter put in, and merging the two makes both unusable.
Fitting notes preserve the subtler judgement around posture, ease, preferences and what should be remembered next time. They are attributed to whoever made them, because a note from the cutter who has made three of your jackets carries different weight from a one-off observation, and a later reader needs to be able to tell.
Nothing is overwritten. A new measurement adds a version rather than replacing the last one, so the record shows the trajectory as well as the current state — which is what lets anyone tell a body that changed from a tape measure that slipped.