CONFIG PROTECT

The CONFIG_PROTECT variable contains a space-delimited list of directories where Portage will not blindly copy over new versions of files, but instead treat the files as configuration files where the user should manually check if the changes are needed and valid or not.

The variable is managed by Portage and contains entries from the users' profile, system environment (which is often used by applications that update the variable through their file) and the users'  setting.

For more information, see Configuration File Protect in the Gentoo Handbook.