they’re using the css :visited attribute on a link to a HN thread to display the message.
having passively followed asahi for some time (too poor to own a mac to actually try it out) the fact that they have to resort to shit like this is gross, but i 100% put the blame on HN for being an unmoderated trashfire (and explicitly bypassing the referrer based blocking asahi first had instead of, idk, actually moderating their site)
https://developer.mozilla.org/en-US/docs/Web/CSS/:visited
Although these styles can change the appearance of colors to the end user, the window.getComputedStyle method will lie and always return the value of the non-:visited color.
OK. I don’t really have an issue with that if they genuinely are having problems with the site.