PHP Phar extension

[sly_roar]

Hello,

According to the documentation of PHP the Phar extension is bundled with PHP as of PHP version 5.3.0, and enabled by default.
http://php.net/manual/en/phar.installation.php

So I thought to use Phar archives for calling PHP classes for running custom Captive Portal. Unfortunately, it appeared that Phar extension does not exist on default installation of PHP 7.2 in pfSense 2.4.4. There is no this extension among packages or other disabled modules.

Proceeding aforementioned, the question is how Phar extension can be enabled or installed?

Thanks in advance.