It’s jsx which is framework agnostic and used in several frameworks but most closely associated with react. It’s easy to convert to html but I guess the author is a react dev and also these icons use framer-motion which is a react animation library to animate the cursor hover. Looks like you can strip those out if you wanted to use these icons in html without animations.
There’s a book about this that hypothesizes that middle eastern cultures naturally developed a disdain for pork because it caused a lot of illness in the hotter climate. When chickens arrived in the region, they filled the same role as pigs (turning trash into meat in a cramped urban environment), while causing fewer serious illnesses. This basically eliminated the need for raising pigs and created a cultural disdain for them. Later, religions from the region codified these ideas.