Just run the package and try to create a panorama image, you will get in your parent xterm: sh: enblend: command not found
enblend? ( >=media-gfx/enblend-2.4 ) <snip> if ! use enblend; then elog "It is recommended to emerge this package with the" elog "enblend use flag to install media-gfx/enblend" elog "that blends the seams between images in a panorama." fi </snip>