Question: Why does Web2Disk add a “.htm” extension to my website page file names?
Answer: To view a website offline your web browser depends on the file extension to determine what type of content the file contains (HTML, images, CSS, JavaScript, etc.). To make Web2Disk work with as many sites as possible (including those written using PHP, Perl, ColdFusion, ASP.NET, etc.), a second extension is added to any downloaded files to ensure that your web browser is able to determine and display the content in all your offline files.
It is possible to disable this feature by unchecking the “Rename Files and Dynamic URLs” option in Advanced Project Settings. Note that when this setting is disabled some sites may not be viewable offline.