Most programming languages have a feature known as generics, which allows you to write functions or data types that work for a variety of data types rather than only one. Here's an example in Java.
public T first;
public T second;
So now you can have a Pair<Integer> which has two Integers, or a Pair<String> which has two Strings, and so on.
Go doesn't have generics. This user has tried to simulate generics by using the ᐸ and ᐳ characters because they resemble < and >, and just copypastes + finds/replaces to create as many different types as he wants. This is not good programming, because Go is not a good programming language.