Web Files Extensions - What are web files and how do I open a web file?

What are web files and how do I open a web file?

File Type Category File Format
.a5w Web Files Alpha Five Webpage File
.ap Web Files Active Page
.asp Web Files Active Server Page
.asr Web Files ActionScript Remote Document
.awm Web Files AllWebMenus Project File
.fwp Web Files Microsoft Expression Web Package
.maff Web Files Mozilla Archive Format File
.rwp Web Files RapidWeaver Package
.url Web Files Internet Shortcut
.wgt Web Files Opera Widget File
.xfdl Web Files XFDL File