torben656 That's because system-devel is a component (a collection of packages), not a package.
You can get a list of them with sudo eopkg lc
.
Also, I recommend you to check the output of sudo eopkg --help
. It's really self-explanatory.
Regards.
[EDIT] Oh, and btw... You can check the list of packages inside a component too: sudo eopkg info -c <component>