Installations

Operating systems:

• http://src.illumos.org/source/ — illumos, FreeBSD, Linux
• http://nxr.netbsd.org/ — NetBSD src and BSD
• http://BXR.SU/ — Super User's BSD Cross Reference — FreeBSD, NetBSD, OpenBSD, DragonFly (very fast)
• http://www.midnightbsd.org/opengrok/ — MidnightBSD, MirBSD and other BSDs
• http://androidxref.com/ — Android

Programming languages:

• http://lxr.php.net/ — PHP

Office and IDE:

• http://opengrok.libreoffice.org/ — LibreOffice

Miscellaneous:

• http://lingrok.org/ — assorted Linux-related projects (fast)
• http://code.metager.de/source/ — almost every open-source project you've ever heard of (expect delays, search takes between 4s and 8s)
• https://opengrok.housegordon.com — GNU (and some non-gnu) projects
• http://src.couchbase.org/source/ — Couchbase DB