I don't think it makes sense to specify the exact format of ebuilds which is designed with binpkgs in mind, but then omit the specification of those binpkgs. Package Managers have already incompatible binpkg formats.
If we're going to spec a binpkg format, let's design a decent one... There's no point speccing Portage's current format.
One thing that users have repeatedly asked for are binpkgs with different USE flag combinations, as in: app-misc/foo-1.2[bar] and app-misc/foo-1.2[-bar] at once. Afais, even pbins don't allow that, unless you install into different e format repositories.
(In reply to Julian Ospald (hasufell) from comment #2) > One thing that users have repeatedly asked for are binpkgs with different > USE flag combinations, as in: app-misc/foo-1.2[bar] and > app-misc/foo-1.2[-bar] at once. Since portage-2.2.19 this is supported when FEATURES=binpkg-multi-instance is enabled (bug 150031).
*** This bug has been marked as a duplicate of bug 672672 ***