Total tangent: What is the magic on that page that renders:
if (putenv (var) != 0)
if (putenv (var) ≠ 0)
When I try to copy that text, it copies as '!=' into my copypaste buffer.
They're using a webfont with a ligature for !=.
Sheeet, I didn't even know that was possible. Why would they use that font for displaying C code? I looked at that ≠ and spent a few minutes trying to figure out what language it was. Maybe I should uncheck the "Allow pages to choose their own fonts, instead of your selections above" option in Firefox, though it woulld probably break other websites.
FYI Fira Code is one example of a very popular programming font that supports ligatures (67k stars on GitHub) [1]. But totally get the frustration of seeing ligatures on the web and not understanding what was going on!