Trace Context Level 2: Self-review for accessibility

[kalyanaj]

This is a self-review based on https://w3c.github.io/apa/fast/checklist.html:

1. Does the technology allow visual rendering of content? No.

2. Does the technology provide author control over color? No.

3. Does the technology provide features to accept user input? No.

4. Does the technology provide user interaction features? No.

5. Does the technology define document semantics? No.

6. Does the technology provide time-based visual media? No.

7. Does the technology provide audio? No.

8. Does the technology provide time limits? No.

9. Does the technology provide text content? No.

10. Does the technology create objects that don't have an inherent text representation? No.

11. Does the technology provide content fallback mechanisms, whether text or other formats? No.

12. Does the technology provide visual graphics? No.

13. Does the technology provide internationalization support? No.

14. Does the technology define accessible alternative features? No.

15. Does the technology provide content directly for end-users? No.

16. Does the technology define an API? No.

17. Does the technology define a transmission protocol? No.