A blog post I wrote on a foreign laptop ended up with byte values 0x92 for apostrophes and 0x93 and 0x94 for quotes. This is an old Windows “smart quotes” and makes sense in Windows code page 1252. It is not valid ISO-Latin-1; that encoding doesn’t have typographical quote marks in it.
Easy enough to fix once the encoding is identified: “iconv -f windows-1252 -t utf-8”
I should make a website that has one web page per code point. So you could go to a page named “0x92.html” and see what all it translates to in the world’s various codecs. There’s a bunch of one-page-per-Unicode-character sites out there, but I don’t know of a resource that lets you easily guess a mystery encoding by a few examples.