Its a situation where one should lookup references, if he did a search for base64decode than maybe he would have known that this is an internal php function, and than maybe experimented, he would have figured out the encoded string..
Than the java portion is a simple algorithm which just creates a string from the ascii decimal values.
If it was me, i usually avoid these questions, only because the op doesnt really care how it all works.
if you just want to remove it, just remove those lines
Code:
$str = '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';
echo base64_decode($str);
but as said before, there should be no reason for you to take credit of other ppls work. All this does is create a frustration with the original authors, and than you wont see any more from him again, and wonder why.