Possible extension (TRL?)
| TRL Level | TRL Name | Typical Open Source Project State | Usability Level (for Users) | Indicators in an Open Source Context |
|---|---|---|---|---|
| TRL 1 | Basic principles observed | Idea, research notes, or early concept | Not usable | Whitepapers, discussions, research repo, no runnable code |
| TRL 2 | Technology concept formulated | Initial architecture or proof sketches | Not usable | Design documents, experimental branches, incomplete prototypes |
| TRL 3 | Experimental proof of concept | Proof-of-concept implementation | Usable only by developers | Minimal code, manual execution, no packaging, unstable APIs |
| TRL 4 | Technology validated in lab | Early prototype | Very limited usability | Runs locally, partial documentation, frequent breaking changes |
| TRL 5 | Technology validated in relevant environment | Functional prototype tested by early adopters | Usable by technical users | Installation instructions exist, example datasets, early feedback loop |
| TRL 6 | Technology demonstrated in relevant environment | Beta-stage open source project | Moderately usable | Releases published, issue tracking active, partial automation, growing community |
| TRL 7 | System prototype in operational environment | Production pilot deployments | Usable by practitioners | Stable core features, upgrade path, CI/CD, real-world users |
| TRL 8 | System complete and qualified | Mature open source software | Highly usable | Good documentation, packages/containers, API stability, security practices, contributor guidelines |
| TRL 9 | Actual system proven in operation | Widely adopted, production-grade open source ecosystem | Very high usability | Large user base, governance model, long-term maintenance, integrations, ecosystem tooling |
Following discussion at TRL support for Status · Issue #292 · publiccodeyml/publiccode.yml · GitHub