Save the output in a file.

Find if the content repeats . Eliminate all the repeating blocks.

We end up with a big chunk of data in last.

Looks like base 64 encoded. Decoding it , we see .png and then some giberrish , maybe base64 encoded png.

convert to hex and try to open as png . But there is an error.

When you see the hexdump , you see the IHDR block is replaced by razi , fix it

You have the flag.