Do you want me to decode or identify that string, or do something else with it?
If it helps, assuming it's standard base64, decoding "XuF0JcyA" produces these bytes:
Those bytes are not valid UTF‑8 text, so it doesn't decode to readable Unicode. Tell me which transformation you want (base64, hex, ROT13, attempt common encodings, try to brute-force) and I’ll proceed.