Welcome to Algorand!
See the discussion on the following topic: Interpreting encoded variables in application info - #5 by fabrice
Concretely, with a Python one-liner:
$ python3 -c "import base64, sys, algosdk; [print(algosdk.encoding.encode_address(base64.b64decode(line.strip()))) for line in sys.stdin if line.strip()]" <<< /sj/9sN19Vz0gYPW8r14ok7IyVFlHrqj7dPpf1wqtwA=
73EP75WDOX2VZ5EBQPLPFPLYUJHMRSKRMUPLVI7N2PUX6XBKW4AOFKMFRI