Sold my first home but received additional dox after fnl closing

[Jessica Hall]

Greetings, 

I recently sold my first home last week using a realtor. The paperwork was completed, signed, notarized by both parties and I receive my wire transfer on Monday as the closing was on a Friday after hours. Friday night I received a document from the realtor of the purchaser. I contacted my realtor but no reply so far. Can anyone tell me what this attachment is? The house was sold "as is", and I paid cash so no loans were taken out when I purchased. I don't want to sign anything that I don't have knowledge of what it is, especially if it didn't come from the realtor I was using.