Another case was in the 2010s on the Gaia spacecraft for which some stray light was identified coming from fibers of the sunshield, protruding beyond the edges of the shield. The Spacecraft Bus is integrated into the whole JWST during construction. The Spacecraft Bus and the Sunshield segment are combined into what's called the Spacecraft Element, which is in turn combined with a combined structure of the Optical Telescope Element and Integrated Science Instrument Module called OTIS. That is the whole observatory, which is mounted to a cone which connects the JWST to the last stage of the Ariane 5 rocket. The Spacecraft Bus is where that cone connects to the rest of JWST.