Validating web resources
Internal links show the author has given attention to the potential needs and questions a reader might have.
Saving to disk or printing a copy of the "pages" you plan to use as source material is a good idea for two reasons.
First, if the site is taken off the Web, the source material will still be available to you.
Second, you can use this print or disk copy of the "pages" to enable readers to verify the credibility of the site if they're unable for any reason to access it online.
It is a RESTful Web service that can be invoked via HTTP to validate metadata and Network Services under the scope of INSPIRE.