i made a similar extension some years ago -- it tries to be fast and injects very little code. i'm curious to know how the performance compares:
Dynamic mode is slower at start, but has no impact on performance after all the stylesheets were analyzed.
does your extension run on android? there are two motivations for nightlight aside from its obvious purpose:
1) be fast on android 2) keep source code simple as possible so everything the extension does is obvious. when i wrote nightlight it was difficult to evaluate the safety of the other extensions at the time, something important to me for a plugin which has full access to all browsing