SSC, the static site checker, is intended for people, like its author, who hand code websites.
It doesn’t just check static sites for broken links, dubious syntax, and bad semantic data, it will actively complain about things that are perfectly legal but rather untidy—also like its author.
Except when examing snippets of HTML or serving CGI queries, it recursively scans the directory seeking HTML & related files to verify. It produces a list of errors, warnings, and other hints of imperfection. Scripts are ignored.
It should not be used on untrusted content; its parsers are holier than Robin’s cow.
You can use SSC from the command line or using it’s native, if rather ancient, GUI interface. You are reading the front page of the help for the GUI interface.
Run SSC, and you should see the welcome dialogue.
For more information on SSC, have a look at the about page.