In 2003, GNOME and Bitstream got together to make some Free fonts for OpenSource projects. The effort resulted in the high quality BitstreamVera font set, which can be downloaded and installed on any system you want. The set consists of the following TrueType fonts:

• Bitstream Vera Serif: a serif font most similar to Georgia.
• Bitstream Vera Sans: a very pleasant sans-serif font. It is similar to Verdana/Helvetica, but wider and warmer.
• Bitstream Vera Sans Mono: a gorgeous monospace font slightly similar to Terminal.

The wiki uses the BitstreamVera fonts if you have them installed.

For more information about the BitstreamVera fonts and downloads see the GNOME's announcement.

The BitstreamVera 1.10 family contains only characters from iso_8859_15(7) ie. Western European charsets, lacking support for characters such as "ā" (A macron, used for example in Māori). There is a fork called DejaVu which aims to cover as much of Unicode as feasible while remaining true to the feel and proportion of the original. (It had to be given a different name because the licence demands this to permit the distribution of modifications.) Nowadays, DejaVu is the preferred family; in fact, some LinuxDistributions no longer provide Packages of Vera, only of DejaVu. If you are using such a distro and want/need Vera as well for some reason, you can following the instructions in FontNotes to install Vera manually.