[zinekeller]

It doesn't cover everyone, but you should know about rel="canonical" (https://datatracker.ietf.org/doc/html/rfc6596). For example, Amazon helpfully hints that this messy Kindle Paperwhite link (https://www.amazon.com/Kindle-Paperwhite-Signature-Essential...) is actually https://www.amazon.com/Kindle-Paperwhite-Signature-Essential....

Additionally, CleanURLs to the rescue! https://github.com/ClearURLs

[karlicoss]

Yeah, sadly, to get the canonical attribute, you need to fetch the URL first (which is slow and wasteful). Also sometimes canonical would still be different on the desktop and mobile version of the site, so it still has to be normalised after that