localhost ~ # emerge -s proto
Searching...
[ Results for search key : proto ]
[ Applications found : 5 ]

*  dev-perl/X11-Protocol
      Latest version available: 0.56
      Latest version installed: [ Not Installed ]
      Size of files: 98 kB
      Homepage:      http://www.cpan.org/modules/by-module/X11/X11-Protocol-0.56.readme
      Description:   Client-side interface to the X11 Protocol
      License:       Artistic X11

*  dev-python/pyprotocols [ Masked ]
      Latest version available: 0.9.3
      Latest version installed: [ Not Installed ]
      Size of files: 331 kB
      Homepage:      http://peak.telecommunity.com/PyProtocols.html
      Description:   Adapter/protocol framework for Python
      License:       ZPL

*  dev-util/cproto
      Latest version available: 4.7e
      Latest version installed: [ Not Installed ]
      Size of files: 142 kB
      Homepage:      http://invisible-island.net/cproto/
      Description:   Generate C function prototypes from C source code
      License:       public-domain

*  net-analyzer/traceproto
      Latest version available: 1.1.1
      Latest version installed: [ Not Installed ]
      Size of files: 132 kB
      Homepage:      http://traceproto.sourceforge.net/
      Description:   A traceroute-like utility that sends packets based on protocol
      License:       GPL-2

*  net-misc/l7-protocols
      Latest version available: 2006.10.18
      Latest version installed: [ Not Installed ]
      Size of files: 114 kB
      Homepage:      http://l7-filter.sourceforge.net/protocols
      Description:   Protocol definitions of l7-filter kernel modules
      License:       GPL-2