Activities Code sample question

I have downloaded the Commerce code samples package for both Commerce R3 and 7.5 and I have a question about the ValidateLineItemsActivities.cs in the OrderGroupActivities folder.
In the function 'PopulateVariationInfo' there is the following code:

// Set new price on line item.
lineItem.ListPrice = newListPrice.Value.Amount;
if (lineItem.Parent.Parent.ProviderId.ToLower().Equals("frontend"))
{
 lineItem.PlacedPrice = newListPrice.Value.Amount;
}

I do not understand what the 'if' statement is for and where the term 'frontend' comes from.

In my code the ProviderId is always empty and therefor a changed ListPrice is not set as PlacedPrice, which is what we want.