The Finger client tool uses an email address as input and communicates using finger protocol to finger servers for information about that email address. This tool has the capability to do a "Finger List" which means it can accept a list of email addresses as input, process them as a batch and display the results of all the queries.
Nearly all servers have discontinued support for the Finger protocol due to security concerns. We have included it for completeness just in case you need it or want to test the finger deamon in Linux. It's kind of a historical curiosity and definitely falls under the category 'Legacy Tool'.