Liberation is the collective name of four TrueTypefont families: Liberation Sans, Liberation Sans Narrow, Liberation Serif and Liberation Mono. These fonts are metric-compatible with Monotype Corporation's Arial, Arial Narrow, Times New Roman, and Courier New (respectively), the most commonly used fonts on Microsoft's Windows operating system and Office suite. Liberation Sans and Liberation Serif were derived from Ascender Sans and Ascender Serif respectively; Liberation Mono uses base designs from Ascender Sans and Ascender Uni Duo.
The Fedora Project, as of version 9 was the first major Linux distribution to include these fonts by default and features a slightly revised versions of the Liberation fonts contributed by Ascender. These include a slashed zero and various changes made for the benefit of internationalization.