FEATURES

The FEATURES variable specifies options which affect how Portage operates and how packages are compiled. It is not used for settings which have a substantial effect upon the resulting generated package.

Relevant FEATURES for developers include:

Feature	Explanation
collision-protect	Raise an error if an installing package attempts to overwrite a file which is provided by a different package.
noauto	When utilizing ebuild, only run the function requested.
sandbox	Enable the sandbox.
sign	GPG sign Manifest files.
strict	Do some extra checks for potentially dangerous situations (eg missing Manifest files).
test	Enable the src_test phase.
userpriv	Drop to non-root privileges for certain phases.
usersandbox	Enables the sandbox even when running non-privileged.