In case the authors are here, the first sentence contains the bytes e2 80 94 which would be UTF-8 for an em dash, but it has been reinterpreted as 3 bytes using https://en.wikipedia.org/wiki/Windows-1252#Code_page_layout and shown on the page as —. Further down, there's a lot of similar errors such as a single right quote (U+2019) in K'nex. Firefox seems to have first removed their encoding configuration menu in version 89, then introduced a new button in version 91, and that one is disabled now as well so there's no fixing this user-side it seems :/
Edit: ah the page is from 2012-03-19, from the <meta property="article:published_time"> tag
Who wants to bet that at some point after the closing of the site, they switched over from a live CMS to a static copy of the site and in the process of doing so things got a little screwed up when exporting data from a MySQL database with the different encoding weirdnesses that can sometimes occur with MySQL and how the db schema was set there.
Yeah this really looks like an encoding issue during migration.
I've run into similar problems when moving old content between systems, especially with MySQL and mixed encodings. It can get messy surprisingly quickly.
If you used UTF-8 then you can probably fix those pretty easily. UTF-8 is sufficiently structured that it’s extremely unlikely for a string that’s written in another encoding to be valid UTF-8 by accident. If you write some code to try decoding as UTF-8 and set that as the encoding when it succeeds, you’re unlikely to damage anything in the process.
I was just mentioning the Japanese word mojibake on the plain-text thread (https://news.ycombinator.com/item?id=47897681), and here you give an example. In fact, UTF-8 misinterpreted as Windows-1252 is the mojibake I personally encounter most often. Curly quotes (most often a right apostrophe inside a word like can't or it's or didn't) are the most common ones, with em dashes being only slightly less common. The other direction (Windows-1252 text being read as UTF-8) produces � (U+FFFD) everywhere instead, but either way, I still see those from time to time today. But far, FAR less frequently than I used to back in the late 2000's or early 2010's. I used to see — and similar sequences all the time 15-20 years ago, and now it's rare enough that I actually notice when it happens.
Edit: ah the page is from 2012-03-19, from the <meta property="article:published_time"> tag