From W3Tech; > PHP is used by 77% of all the websites whose server-side programming language we know. I had a quick look at the methodology section, but it’s not clear to me how accurate this data is. Determining whether a site uses PHP can be relatively straightforward (especially with default extensions / if Wordpress is used / etc), but if a site (potentially using a different language) is behind a reverse proxy/u…
I agree. I always doubted these figures (I'm a PHP dev myself, so I wouldn't mind these figures being true). I think the methodology is shady. I wonder if they use what the server indicates. I think some servers like Apache with php mod send this information to the client in a header. But most servers don't. Therefore they maybe use this as "from all the servers giving a backend language information, PHP represents 7…
No need to speculate about how it works.
tl;dr A lot more than looking at Apache headers or WordPress meta tags.