On: So, I looked at Plesk's 404 Page

[btn]

Short messages are usually of the form "404 - File not Found". These are non-informative for many users ("what does it mean?"), don't give any recovery options ("what can I do now?"), and aren't localised.

[moeffju → btn]

And this is a perfect example of an uninformative error page. Why they felt the need to pad it out, I don't know.

[Semiapies → moeffju]

Because it's a default error page intended to be customized.