CONFIG PROTECT MASK
The CONFIG_PROTECT_MASK variable contains a list of files or subdirectories which will be excluded from the overwrite protection offered by the CONFIG_PROTECT variable. This is to say that files or subdirectories mentioned in this variable will be overwritten by Portage upon (re)installation.
"Masking" is useful when locations within a certain parent directory are protected from automatic overwrites - excluded from the package manager's control, but a certain child location should be included in the package manager's control.
- CONFIG_PROTECT — contains a space-delimited list of files and/or directories that Portage will protect from automatic modification.
- savedconfig — a USE flag that preserves the saved configuration files upon package updates.
- /etc/portage/make.conf — the main configuration file used to customize the Portage environment on a global level., the location Portage keeps binary packages.