{
 "metric": "mta-sts",
 "segment": "gb",
 "anchor": "domain",
 "label": "the UK (domains)",
 "population": "domains in the UK",
 "states": [
  "enforce",
  "testing",
  "absent"
 ],
 "quiet_failure_states": [
  "testing",
  "absent"
 ],
 "measurement": "Tier 0 + 3a. TXT at `_mta-sts.<domain>`; if present, fetch `https://mta- sts.<domain>/.well-known/mta-sts.txt` and read `mode`. Denominator: `has_mx`.",
 "why_it_matters": "The declared-vs-enforcing split is exactly the brand thesis. `mode: testing` publishes a policy, produces reports, and does not require TLS — downgrade attacks still work. The DNS record alone looks like adoption; only the fetched policy reveals whether it bites.",
 "limits": null,
 "data_tier": "dns",
 "population_predicate": "has_mx",
 "entity_type": "domain",
 "kind": "failure",
 "latest": {
  "day": "2026-08-10",
  "n": 197,
  "qf_pct": 99.49,
  "ci": [
   97.18,
   99.91
  ],
  "dist": {
   "enforce": 0.51,
   "testing": 0.51,
   "absent": 98.98
  },
  "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
 },
 "series": [
  {
   "day": "2026-08-01",
   "n": 70,
   "qf_pct": 100,
   "ci": [
    94.8,
    100
   ],
   "dist": {
    "enforce": 0,
    "testing": 0,
    "absent": 100
   },
   "snapshot": "common-crawl-domain-stratified-c150-g2500-seed20260729"
  },
  {
   "day": "2026-08-03",
   "n": 68,
   "qf_pct": 100,
   "ci": [
    94.65,
    100
   ],
   "dist": {
    "enforce": 0,
    "testing": 0,
    "absent": 100
   },
   "snapshot": "common-crawl-domain-stratified-c150-g2500-seed20260729"
  },
  {
   "day": "2026-08-05",
   "n": 197,
   "qf_pct": 99.49,
   "ci": [
    97.18,
    99.91
   ],
   "dist": {
    "enforce": 0.51,
    "testing": 0.51,
    "absent": 98.98
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  },
  {
   "day": "2026-08-10",
   "n": 197,
   "qf_pct": 99.49,
   "ci": [
    97.18,
    99.91
   ],
   "dist": {
    "enforce": 0.51,
    "testing": 0.51,
    "absent": 98.98
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  }
 ],
 "license": "CC BY 4.0",
 "source": "https://quietfailures.com/datasets/mta-sts/gb"
}