(Research scientists have broken down Luciferase into more than 1,000 proteins, but they still do not know how the heatless light is produced. Someone someday may figure out how God made this heatless light. Need I say that they will join the ranks of the righ and famous?)
When I did a proposition oral on chemiluminescence 31 years ago, it was pretty durn well understood - though I'd have to go back to the library to give you the precise details on how this light is produced. Many luciferins involve breaking of a dioxetane ring and subsequent singlet -> triplet conversion of the radicals formed.
And that "1000 proteins" bit is complete nonsense! There are lots of different luciferases, and the biggest I know of is a single protein. Many are small molecules.