The color bars you see at top are a way to monitor the progressive color builds and keep the colors accurate across a large print run (which the SW toys no doubt were). Progressive means that the colors are usually printed Y C M K (spot, varnish / UV coat) by separate printing plates in a printing press. The K black plate covers/overprints last (black = C+M+Y) and helps cover boundaries where there are multiple colors. They can also have dot gain, stars (shows resolution through multiple generations / whether the negatives are sharp or overexposed) and other quality control things along with trim marks and guides and are usually trimmed die cuts (think of an industrial cookie cutter) in this case which rounds the corners and punches the hang hole.
The color bars are usually checked with a densitometer by either pulling a few sheets at different points in the run or through in-line computer control these days. All these things + the artwork, typography, etc. are part of the negatives made from the artwork that are used to "burn" the plates for the printing press. If you look inside most boxes (Triscuits, Oreos, etc.) you'll see the same sorts of marks. Consistent color is a big deal to large companies in that their corporate image become associated with the colors. Color fidelity is also critical when printing pictures that we all know from movies or ones with lots of flesh tone; we're all very sensitive to photos that "don't look right" are too yellow, etc.
If you have samples of different parts of the print run, you can also see things like color variance over the run, paper changes, whether they were running the press too fast ( for "late" products or huge unexpected sales) ink "tears", ink that doesn't have time to dry (it looks like teary mascara towards a margin) before the next color and what way the paper was run through the press (paper is like wood in that it has an optimal direction to move through a press). Muddy images are another symptom of either poorly produced art or too-fast printing.
The bars usually consist of C M Y K (Cyan Magenta Yellow and Black) plus any spot colors and also the "progressive build" of the individual colors. All are useful for debugging printing problems. Spot colors are used for things like the Oreo Blue along with the cookie photo. Spot also doesn't have the "rosette" pattern that can sometimes be detected from CMYK color separations. Pantone is one spot-ink maker.
Revenge of the Jedi Millennium Falcon Proof Sheet
Uncut Biker Scout Proof Card
Revenge of the Jedi Logo Proof Sheet
Description: Jim R. (firstname.lastname@example.org)