I frequently visit https://news.ycombinator.com/active and sometimes I accidentally type https://news.ycombinator.com/ACTIVE which provides me with a nice
Unknown.
message...
Should a URL string be case insensitive or does it actually matter?
While the host part is case-insensitive, the path is case-sensitive on almost every website. In principle a website could choose to do a case-insensitive match, but I can't think of one that does.