Why does PHPStorm ask me to include native PHP extensions inside composer?

I'm new to PHPStorm and i've been noticing that it recommends me to add native PHP entensions like PDO and Openssl to my composer.json

Why does it do that? 

In this pic its recommending i install `ext-openssl` 



I didn't even know there was a composer package for it, I looked it up on packagist and I couldn't find that package there…I didn't go ahead with the install so im not sure where it would be pulling the package from. Anyone knows?

Also, why does it make those recommendations, the same for PDO, I'm guessing its in case a server doesn't have those extensions but those are quite common extensions available with PHP out of the box (as far as im aware)