Impress comes with five prepackaged slide masters. They are shown in the Master Pages section of the Tasks pane. This section has three subsections: Used in This Presentation, Recently Used, and Available for Use. Click the + sign next to the name of a subsection to expand it to show thumbnails of the slides, or click the – sign to collapse the subsection to hide the thumbnails.
Available master pages (slides)
Each of the slide masters shown in the Available for Use list is from a template of the same name. If you have created your own templates, or added templates from other sources, slide masters from those templates will also appear in this list.