Datadog application keys (legacy 40-hex)

• trufflehog 3.97.4
• gitleaks 8.30.1

The pre-ddapp_ application key: a bare 40-character lowercase-hex value with no marker of its own, so, like datadog-api-key, it is scored as policy and only beside a same-line DD_APPLICATION_KEY / datadog marker. Datadog documents no grammar for it; trufflehog 3.97.4's datadogtoken detector and gitleaks 8.30.1's datadog-access-token rule (keyword- and assignment-gated `[a-z0-9]{40}`) both corroborate the 40-byte width, and Datadog's own validators (the Agent app-key check in keys.go, the CloudFormation and ARM templates cited on the datadog-application-key contract) accept `[a-f0-9]{40}` as an alternative to `ddapp_[a-zA-Z0-9]{34}`, so the generation stays live. Re-checked 2026-09-23 (redact-secret#671, PR #679): the product split this shape into its own `datadog-application-key-legacy` detector with the same same-line context gate; the benchmark family follows the product's registry, and the length twin rests on the tool and validator corroboration above rather than a provider page.