If you use Blogger, you may sometimes want to backup or move your blog data outside of Blogger. To do this, you'd normally log into your Blogger blog, go to the Settings tab, click on Export blog at the top of the page, then click the big orange Download Blog button.
But unless you also have allowed your blog feeds to "full", you'd only download a short portion of each of your blog entires (not so great for backups!).
To enable the "full" blog feed, again go to the Settings tab, then click on the Site Feed sub-tab, and then select Full in the drop-down menu next to the Allow Blog Feeds setting.