What do all these file names mean?

.html	An ordinary web page. View using your web browser
.doc	A Microsoft Word document; to view or print these files, you will need to save the file to your local computer and then use Microsoft Word, or another compatible word processing program.
.pdf	Portable Document Format, for printing. Can be viewed in your browser or downloaded to your local computer, depending on your browser settings. You will need a PDF viewer to use these documents. Adobe Software provide a free PDF viewer for downloading to your local computer.
.ppt	A Microsoft Powerpoint document; to view or print these files, you will need to save the file to your local computer and then use Microsoft Powerpoint, or another compatible presentation program.

EDINA is the Jisc-designated national data centre at the University of Edinburgh.