localhost portage # nano -w package.keywords 
localhost portage # emerge =x11-plugins/e_modules-9999
Calculating dependencies \
!!! All ebuilds that could satisfy "=x11-plugins/e_modules-9999" have been masked.
!!! One of the following masked packages is required to complete your request:
- x11-plugins/e_modules-9999 (masked by: missing keyword)

For more information, see MASKED PACKAGES section in the emerge man page or 
refer to the Gentoo Handbook.