OPML, or Outline Processor Markup Language, is a file format for exchanging outline structured information between programs that are running on different operating systems. OPML is based on the XML programming language. OPML is used by many RSS readers to store bookmark information. If you have bookmarks on your web browser, you may want to export them to OPM for your RSS reader. You can do this with the Mozilla Firefox browser and the OPML Support extension.
Download the OPML Support add-on from Mozilla Add-ons. (See Resources.) Click "Add to Firefox," and this functionality will be integrated into Firefox the next time you open up your browser.
Open Firefox and click on the "Bookmarks" menu in the top menu bar. Select "Organize Bookmarks."
Click the "File" menu on a PC. Click the far-right menu button in the "Library" window on a Mac.
Select "Export." Click on "Export OPML" from the menu.