Short answer
Convert a Unix timestamp to a readable date when you need to inspect an API value, log entry, database field, or event time. Convert in the other direction when a system expects Unix time.
When this applies
Start by identifying the unit and timezone. A 10-digit value is commonly seconds and a 13-digit value is commonly milliseconds; the display timezone changes the readable date, not the instant represented by the timestamp.
Practical review steps
- Keep the original value with its source system or API field name.
- Confirm seconds versus milliseconds before accepting the date.
- Record the timezone used when comparing a timestamp with a displayed time.
Check the actual color pair
Use the free Time Shift with the foreground and background colors from the real component. It provides an immediate AA and AAA ratio check in the current browser tab.
Source and limit
For the formal requirement, review W3C's WCAG contrast minimum guidance. A ratio result checks a color pair; it is not a complete accessibility audit.