In 2007 https://news.ycombinator.com/item?id=63294 the median age was 25.5 and mean 27.3. In 2022 (15 years later) https://news.ycombinator.com/item?id=30897468 the median age using midpoints was between 35.44 and mean age was 37.22. If we presume that older folks tend to not answer these (so polls skew young), then I think it's safe to say young-Gen-X to older-millenial is the core demographic here.