`/v1/advisories/summary` — canonical advisory counts by headline severity band. The summary reads the same projection as the browse list so every count describes one published browser generation.

curl -X GET "https://example.com/v1/advisories/summary"

{  "critical": 0,  "high": 0,  "low": 0,  "medium": 0,  "total": 0,  "unscored": 0}