I similarly contribute only minor language and writing corrections to Wikipedia, and usually anonymously (unless my phone has randomly pulled a blocked IP and I need to sign in). I don’t consider myself enough of an expert in any Wiki-worthy topic to do anything more, but I’ll make damn sure small mistakes get addressed.
I feel even less qualified to contribute corrections on GitHub mostly for the same reasons mentioned above. Staying anonymous prevents anyone from thinking I’m attempting to capitalize on low hanging fruit.