PHP 8.0 Version

If you just want to patch the original plugin here is the patch from the changes on the DuckDivers repo:

https://gist.githubusercontent.com/dieppon/bfd57f1765260eff2e76da5da7ee0c26/raw/4b228286277f5afd280391faa51b176074af4221/kint-debugger-php-8-0-version.patch

Download:
https://raw.githubusercontent.com/kint-php/kint/master/build/kint.phar

Then create a folder in plugins called my_kint with two files:
my_kint.php
kint.phar

in my_kint.php add the following code:

<?php
/*
Plugin Name: My Kint
Description: Kint Debugging Tool
Version: 1
*/
include 'kint.phar';