Microsoft Office 2007 documents are zipped XML files. For example, you can change a Word document’s extension from
.zip and unzip it. Apparently this isn’t widely known; most people I talk to are surprised when I mention this.
I’ve found a couple uses for the
zip/XML format. One is that you can unzip a document and grab all the embedded content. For example,
.jpeg images are simply files that are zipped up into the Office document.
Another use is that you can crack open a document’s underlying XML to search for something you can’t find via the user interface. You can unzip Office documents, tweak them, and zip them back up. I don’t recommend this, but I’ve done it when I was desperate. (Microsoft publishes an API for manipulating Office files. Using the official APIs is safer and in the long run easier, but I haven’t looked into it.)