How can I check what is installed in PHP? Such as Libraries, extensions, et cetera
You can easily check the installed PHP extenstions, libraries, and what not with the phpinfo() command. For example, from the command line you can check for PHP cURL support with grep:
php -r 'phpinfo();' | grep -i curl
You can also create the phpinfo as a webpage. You can find further instructions on
this Community question.