How can I find the documentation for the `??=` operator?

Imagine I'm a newbie and I see the ??= operator in some code. How can I learn about it?

1. What is the type of this operator? When I visit the Operators help page https://www.php.net/manual/en/language.operators.php, I can't find it by searching on the page.
2. I'm clicking randomly on the operator type pages (Operator Precedence, Arithmetic, etc). I can find that it's an Assignment operator on the Operator Precedence page. But when I get to the https://www.php.net/manual/en/language.operators.assignment.php page, I can't find any description. This operator is mentioned in the Other Assignment Operators section with no description, just another type of the operator.
3. Okay, I see that this operator is mentioned as Null Coalesce in the Other Assignment Operators section. When I go to the https://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.coalesce page, there's NO description of this operator, it is not mentioned anywhere.
4. Okay, let me try the search field of the php.net website. But again nothing, I get ??= doesn't exist.
5. When I try searching in Google "??=" site:php.net I'm still getting nothing.

Why is getting information about this "secret" operator so difficult? I would suggest the following improvements:

• Mentioning all existing operators on the Operators help page to enable users to quickly identify the type of operator they're looking for by using the browser's search on page function. It probably should be a table with links to corresponding help pages.
• Add explicit documentation for the ??= operator to a corresponding help page.

Start with the Operators, assignment operators, and comparison operator pages linked in the issue, then trace how the ??= operator is currently referenced. Document the operator explicitly and make it discoverable from the Operators page and site search; done means users can identify its type and find its description through the documentation.