Below are the types of transactions and corresponding table name for each. 

Donation - DonationTransactions
Event Registration - EventTransactions
Membership - MembershipTransactions
Profile Update - ProfileUpdateTransactions
Signup (as in Website Registration) - SignupTransactions

The following script is an example as to how to query on the XML to find donation transaction(s) where the term "BlackbaudSupport" was used in any field. Note that the table name below can be changed from DonationTransactions to any of the other tables listed above to find details about other types of transactions as needed.

select * from Donationtransactions 
where cast(xmlobjectdata as nVarchar(Max))
like '%BlackbaudSupport%'