如何知道我是否使用了作曲家依赖？

Question

Here is my composer.json file, saved at /var/www/vhosts on production:

{
  "require": {
    "php": ">=7.2.0",
    "ext-curl": "*",
    "authorizenet/authorizenet": ">=1.8.8",
    "jms/serializer": "xsd2php-dev as 0.18.0",
    "google/apiclient": "^2.0",
    "nategood/httpful": "^0.2.20",
    "ezyang/htmlpurifier": "4.7.0",
    "pear-pear.horde.org/Horde_Imap_Client": "*",
    "ssilence/php-imap-client": "dev-master"
  },
  "repositories": [
    {
      "type": "pear",
      "url": "https://pear.horde.org"
    }
  ],
  "config": {
    "secure-http": false
  },
  "minimum-stability": "dev",
  "prefer-stable": true,
  "require-dev": {
    "phpstan/phpstan": "^0.9.2"
  }
}

All PHP code for this server (including cron and local scripts) is saved inside /var/www/vhosts.

I would like to remove dependencies from this file if I am not using them.

For each item ("ext-curl" ... "ssilence/php-imap-client"), how may I identify if I am using that package?

Back before autoloader, this was a simple task and I could grep for pear-pear.horde.org/Horde_Imap_Client, but now this might be more difficult.