W3C License
Whiskey Ware
Do What The Fuck You Want To Public License
wxWindows Library License
xdoclet-2 license
xdoclet-2-plugins-license
XFree86® Project Licence (version 1.1)
xinetd
X.Net License
YAML under Commercial License
Yahoo! Public License, Version 1.1
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Zope Public License
Zope Public License (ZPL) Version 2.1
Zimbra Public License, Version 1.2
ZXGE Public License