Can't find any such file on either of my W10 systems. There are, though, several files on my W7 system with an .old extension, either on its own or appended to another.
BTW I follow my old boss's practice - on getting a new computer I just add it to the network, keeping the existing ones to run legacy stuff.
By clicking on the User Name, you will requery the forum for that user. You will see everything that he or she has posted with that Mudcat name.
By clicking on the Thread Name, you will be sent to the Forum on that thread as if you selected it from the main Mudcat Forum page.
By clicking on the Subject, you will also go to the thread as if you selected it from the original Forum page, but also go directly to that particular message.
By clicking on the Date (Posted), you will dig out every message posted that day.
sj