Using dll Refresh file in Web Site Project

To be user that I have the correct file types and extensions in my project, I will like to ask this.

I have an iText package in my work and it has files with extensions as (.dll and .dll.refresh)

The (.dll) has a Type as (Application extension) and (.dll.refresh) has a Type as (REFRESH File)

I hope that the File Types belonging to the packages are correct File Types?