Apparently, there are some daredevils out there who assemble this Nu Gundam, then disassemble it, strip off the plating, paint it all over, and then reassemble it. I think that's impressive, but I'm not up to that level, so I'll just go at my own pace.
(Part 4)
https://www.gn-app.com/posts/3442cd13-9d20-4ff4-9fc8-5afba9cc4e83
Now we come to the chest area. This is where the LED unit comes in. However, since the Nu Gundam's light is concentrated around the chest, it wasn't anything particularly novel. With the PG Exia, the light extended to the limbs.

PGU-ν Gundam Progress ⑤ | でぐでぐ's Gunpla works