Larry Wall, the creator of the Perl and Raku programming languages is famously a linguist. I was very surprised not to see him or his creations mentioned in this article.
That is, when I'm talking to a human, I say "read in a line of text. If it ends in a newline, remove it". A human understands that. But a programming language says, "Read the line in from where? Read the into what variable? And, if what ends in a newline?"
But Perl has a default place to read input from, so if that works, you can just say "read in a line" without specifying from where. And it has a default variable, which is where the line will be stored if you don't specify somewhere else. That variable plays the role of "it" - it's what we're talking about if we don't specify something else. So "if it ends in a newline" means "if the default variable ends in a newline" without having to actually specify that I mean that variable.
It's very handy. And, like "it" in English, it can also cause confusion.
But I (a non-linguist) think it's linguistically interesting.
The other function is as a dummy subject, as in "it rained", "it's cold". English grammar requires a subject (unlike many other languages, where a pronoun in subject position can be ommitted without the sentence becoming ungrammatical). So here "it" doesn't refer to anything, it's (haha) just there to fulfill a syntactic requirement
t. linguist
eg:
some_list_of_things.each { print(it) }