This is a question that was asked by one of the leading CMS companies about their product and I am not sure what they mean by this.
Do you have a resx key - GoBack and resx file for ContentViewSingleItem.ascx
Can someone maybe tell me what a resx key is?
Thanks
It's the key with which you can obtain a value from a resource (.resx) file. This is used in the context of localization where, depending on the culture, the application gets the value from the correct resource.
To read more about it take a look at ASP.NET Web Page Resources Overview.