Preview Docs от Francesco De Stefano

WebExtension that lets you preview dozens of types of documents before you download them. Just hover over a file's link, and PreviewDocs will display an interactive preview of the file instantly.

PreviewDocs supports previews for the following file formats:
* PDF and RTF Files
* Word Documents (.doc, .docx)
* Excel Documents (.xls, .xlsx)
* PowerPoint Presentations (.ppt, .pptx)
* WebM, MP4, GIFV, and OGG/OGV Video
* MP3 and WAV Audio
* Previews are created for content on https pages
* The extension includes a settings page where you can set with which service you want to preview the files and limit the previews of the contents