Pfl

Portage File List (PFL) can be Article description::used to search for files (or strings) provided by packages that are not currently installed on a given system. This can be useful to find out what package to install given the name of a file from a desired tool. Optionally, the PFL tool can update the online PFL database from the list of locally installed files.

While most Linux distributions are provided as package archives of files to be installed, Gentoo is a metadistribution: the files to make up each package are generated on the user machine, just before installation, according to the current system configuration (USE flags, CFLAGS etc. see make.conf). As each system's files are generated just before a package is installed, there is no fixed central reference of all the files that make up Gentoo. There are so many possible system configurations that it would be impractical to build such a list on a centralized system.

PFL gets around this by querying participating user's machines to determine lists of files generated upon installation. These lists are uploaded, anonymously and with the user's permission, to the PFL server, to allow anyone to query what packages can provide a file with a given name.

The PFL should reference most file names that can be installed by Portage, though in practice there may be exceptions.

may be used to determine what package a locally installed file comes from. PFL may be used as a faster alternative, but only will be able to reliably determine this on a given machine.

Emerge
You can install with the following command:

Usage
The database can be used online to search for files installed by ebuilds. Lets say you want to run but it isn't installed. Recently the program was removed from itself, so you could search for  online to find the related package: search online

Search time comparison with equery
Here is a result of search times compared to :

PFL is much quicker to search files (even if not installed locally), while is more powerful and gives more options to search.