The etc tarball has a readme that says this: 

> This package contains icons that are displayed by Gnus when running
> under XEmacs.

If that's the case x-splash really ought to be in the standard etc directory
in the gnus/pgnus tarballs as well. Most Emacs users never bother to install
the etc tarball precisely because it's mostly only useful under XEmacs.

For example, Emacs itself hasn't ever put the gnus etc tarball into its etc
directory. If they exclude it again when they integrate 5.6 they'll never see
the pretty gnu. :(

greg