You can't export secured content. For obvious reasons.
Now what you can do is make modifications to secure content. This is awesome! Picture this use case:
- The D&D 5e SRD contains all of the monsters but none of the monsters pictures, descriptions, etc. Every-time you import the content you are therefore lacking the pictures etc.
- Import the SRD into a realm.
- Adds pictures.
- Add descriptions.
- Export the content.
- Now you have an import pack that can be imported over the top of any SRD installation and it will re-apply the changes. You only need to update the pack once with the changes you want.
This is very powerful given most providers in this situation would simply block you from modifying or sharing the content.