Based on my research, assets are currently a Prefect Cloud feature and there hasn't been any official announcement about bringing them to the open-source version yet. The feature allows for dynamic visualization of data workflows and includes capabilities like visual state indicators and automatic dbt lineage.
While Prefect is actively developing and expanding the assets feature set (including enhanced integration libraries and data quality monitoring), the current implementation appears to be tied to Prefect Cloud. If you're interested in using assets, you would need to use Prefect Cloud at this time.
You can learn more about the assets feature in the official blog post:
https://www.prefect.io/blog/introducing-assets-from-task-to-materialize
If you're specifically interested in using assets in an open-source context, I'd recommend keeping an eye on Prefect's GitHub repository or community channels for any future announcements about broader availability.