I notice that my PHP code contain special numbers (e.g. _5b9652a96785) representing variables:

<?php
include_once('../include/config.php');include_once('../class/db.php');if (isset($_POST["points"])) {$_5420457f97cc = json_decode(stripslashes($_POST["points"]), true);$_a095ff903bcc = trim($_5420457f97cc["itemName"]);$_58f60403479c = trim($_5420457f97cc["itemCost"]);$_bb2bde3e818f = trim($_5420457f97cc["itemPrice"]);$_5b9652a96785 = $_5420457f97cc["itemUnit"];$_03d9de238649 = $_5420457f97cc["itemCategory"];$_22f632d073d5 = $_5420457f97cc["ingredientArray"];$_83647d4cbbd0 = new dbPdoMysql;$_6445f036fed3 = $_83647d4cbbd0->dbInsertItem($_a095ff903bcc,$_5b9652a96785,$_03d9de238649,$_58f60403479c,$_bb2bde3e818f, $_22f632d073d5);if ($_6445f036fed3 == true){echo "true";}else{echo "false";}}else{}?>

What does the special numbers mean and how can it be converted back to a meaninful representation?

That is obfuscated code, somehow I doubt it's yours. If it is, just start renaming.

I found an online tool to reverse the obfuscated code. I own the code but the developer intentionally obfuscated the code.

I own the code but the developer intentionally obfuscated the code.

Looks like he disagrees...