Just what is << pseudo: before >> </ <pseudo: before >> and is it useful to me?

Question

While playing in Chrome, I noticed that if you copy a pseudo-element (for example ::before) from the element inspector and paste the results, you will get the following:

<<pseudo:before>></<pseudo:before>>

I cannot find a link to this syntax, and I was wondering:

• Is this just a way for Chrome / webkit to allow pseudo-element checking in dev tools, or is this part of a wider specification?
• Are there any cases / reasons why this may be useful for the developer, for example (perhaps unlikely) that displays this syntax directly to emulate the CSS pseudo selector?

Answer 1

info: The outerHTML attribute ::before pseudo-element DOM.

element "" , ^{( CSS content:'')}...
... outerHTML ^{(& paste)}

, AFAIK, / pseudo-element DOM.

---

... outerHTML ... Javascript /, , .

---

: , outerHTML Chrome DevTools.

#question-header h1:before {
    content: 'Hi there! ';
    color: red;
}