RB wanted a quick way to see if an item is linked to a URL, File or
Outlook E-mail. In other words, if the item has a link in the Net
Location Folder.
 
The following LUA script will append {NL} at the end of the item text
to indicate that the item has a link.
 
Code:

++:L:
A=get_folder_value("Net Location",item_id)
B=get_item_text(item_id)
C=string.find(B, "{NL}")
if (A~=""and C==nil) then
text=B .. " {NL}"
set_item_text(item_id,text)
end
 

Simply create a new folder and add the rule to it. (I added a
checkmark folder called "LUA Rules").
You can update already existing Items by running "Check Folder Rules"
on the "LUA Rules" folder.