The browser extensions are used to open links to local files directly by clicking on the link in the browser.
After the installation of the browser extensions, simply click on the link as you would for a normal hyperlink. Instead of opening another page in the browser the file is opened with the appropriate application.
Please note that these browser extensions can be a security risk. Only click on links to local files if you know that the website that the link is originating from can be trusted (i.e. your company’s local intranet server).