Well, I created a PHP page as follows:
<?php
$x = "h\164tp\163\072\057\057\x70r\157\x64\x75\x63t-\x73\x65a\x72\143\150\056\x61\160i\x2e\x63\x6a\x2ec\x6f\x6d\057v\062/\160\x72\157\x64\165\x63t\x2ds\x65\141\162\143\x68\x3f";
print $x;
?>
and ran it.
And I got the following:
https://product-search.api.cj.com/v2/product-search?
Which means nothing to me, except that cj.com is part of Commission Junction, which is an online advertising network.
It's been deliberately obfuscated, so clearly the person who wrote it intended that you didn't notice it or understand it, and would leave it alone. I don't know the context of the question, why you're asking about it, but my guess would be that you've been hacked and someone has inserted this code (and more) into your site.
If that's the case, their aim would clearly be to gain some advertising revenue by freeloading on your site. Not particularly malicious as hacks go, but not something you'd want to be happening (especially if you don't know what kind of ads would be shown).
https://product-search.api.cj.com/v2/product-search?