Here is the answer I sent you, so anyone can profit from it:
What you have there is a package file (see the little folder icon). There
are two possibilities:
1. It's a package file you have. To verify this case, remove your mods
folder, delete your cache-files, start a new game and see if it's still
there. If yes, it's option 2, if it's gone, try putting the package files
back in groups until you find the culprit.
2. Some stuff comes with the Sims Package Files. They don't show in
custard or your launcher an can only be deleted by deleting the sim that
has them. So you will need to uninstall all your sims and households (or
one by one) until it's gone.
Hope that helps.
