Javascript 符号是什么<；和/意味着在这个Firefox堆栈跟踪中？

我在Firefox中抛出了一个JavaScript错误，但在Chrome中没有。Firefox开发工具控制台窗口中的堆栈跟踪如下所示。例外情况发生在

---

我想知道符号

您是否看到符号
/
和

TypeError: a is null
    p</G()
    p</Y()
    p</$()
    M</f/this.normalize/a()
    M</f/this.normalize()
    U/this.currentStyle()
    ...

function fn1() {
    function fn2() {
        // At this line the stack trace in Firefox will look like:
        // fn1/fn2@file.js - function fn2, which is nested in fn1
        // fn1@file.js     - called from function fn1
        // @file.js        - called from global code
    }
}

fn1();

const sum = (a, b) => a + b;
// The arrow function will be named as "sum"

const sum = numbers.reduce((a, b) => a + b);
// The arrow function will be named as "sum<"
// This means "a helper function used in computing sum"

const fn1 = (function(fn) {
    return function() {
        fn();
    }
}(function() {
    // At this line the stack trace in Firefox will look like:
    // fn1<@file.js - anonymous function from a closure in function fn1
    // fn1@file.js  - called from function fn1
    // @file.js     - called from global code
}));

fn1();

function f() {
    var filtered = data.filter(function () {
        // The name for this function is "f/filtered<"
    });

    filtered.forEach(function() {
        // The name for this function is "f/<"
    });
}