PHP: How to check whether a library has been properly installed and enabled?

Question

Following another question on SO (I am no PHP expert), I am wondering whether the Zlib library has been properly installed on my local laptop. Documentation says there shoul

Answer 1

Make sure that, if you are using DevDesktop, you are referencing the Application/Devdesktop/php# version of PHP(links within DD prefs) (my dev machine has three: Mac OS, HomeBrew, and Acquia DevD)..

I used Homebrew to tap that ^ keg and install the plugin (Mac).