Why are triggers and rules under package in manifest.yml?

From the OpenWhisk getting started [documentation](https://console.ng.bluemix.net/docs/openwhisk/openwhisk_triggers_rules.html#openwhisk_triggers):
>Triggers cannot be created inside a package; they must be created directly under a namespace.

So why are triggers and rules underneath package in manifest.yml?

```
package:
actions:
...
triggers:
...
rules:
...

```