Github iconography is built on nomenclature where accent is on open / closed state of things, presumably to signal their availability. "Open bug" icon is green as in "available for work" and closed bug is red as in "not available" .
In my head it is mostly the other way around, because I'd emphasize the "danger" nature of things: unresolved bug is "bad and dangerous", so its colour should be red, but resolved bug is "good", so it should be green.
This style tries to swap those colour wherever it aligns with my interpretation. Semiotic interpretation? Maybe.
 it is even more convoluted, because "open bug" icon is exclamation mark in circle (what seems understandable) which is green. Closed bug is some weird mutant of exclamation and check mark, which is red.