Just set up a separate script, copy and paste one encoded string at a time into it in a base64_decode() function and echo the result. See what it spits out, and repeat as necessary. Then arrange all the separate bits together and see what you get.
Sure, it's tedious, but it's your code, so you're the lucky one who gets to do it. 😉
PS: It looks like the code you posted is incomplete in any case: the print(), the base64_decode() and the string within it are never closed.