sql server – What does Nested Loops join operator has to do with a Scalar?

As far as I understand the docs, the Nested Loops operator is a join operator, i.e., it requires two tables as input.

If that’s correct, then why the Nested Loops operator is used with a Scalar input?

For example, take the following query (from Paul White’s website) and its execution plan.
You can see that the inputs for the Nested Loops operator are (1) a Scalar, and (2) a table (the result of the Index Seek).

I know that a scalar can’t be joined with a table, then what that actually means? What’s actually being joined?

USE AdventureWorks2019;
DECLARE @Like nvarchar(50) = N'D%';
SELECT p.(Name)
FROM   Production.Product AS p
WHERE  p.(Name) LIKE @Like;

enter image description here

BTW, I presume that it’s a pretty basic question, but I couldn’t find a good resource that goes through such basics methodologically, so a recommendation would be much appreciated.