When someone posts a rather long code fragment in chat it is shortened and a link to a separate page is created. The linked page is send as
text/plain. But the code is escaped as HTML.
This makes the code hard to read. It is not necessary.
The intended scenario there is that the sample is opened inline via the expansion link provided, hence why it is formatted . I'm not sure it ever occurred to me that people would try opening it as a separate page. However, what you say is not an unreasonable usage. I'll see what we can do.