Latest Updates

When I update the files on my site the files updated appear in “latest updates”
http://www.fleetwood-trawlers.info/index.php/latest-updates/

What appears there (if I recall correctly) depends on the prefix of the title of the permalink.

E.G. anything titled S.T. would appear as an update, such as S.T.Pretoria FD212.
I did have it set to display any file prefixed S.D/T. but this seems to have vanished and I can’t recall which file I edited to get it to appear, and I can’t find it again.
I’m assuming that it got overwritten in an update.

Can someone point me in the right direction please?

Thanks

Jim