These question mark links produce help text when you hover your mouse cursor over them. In case your client does not support displaying HTML title attributes, here is the text for the link you clicked:

The type of the output. Valuto only sends a few different types of transactions. 'Address' sends to an Valuto address. 'Pubkey' sends directly to a public key, and is used for IP transactions and generations. 'Strange' is an unusual transaction not created by the official Valuto client. It's also possible for transactions to have several different types of outputs