Tracker not in the catalogue: a request a public blocklist names but no vendor owns

What an unidentified tracker is

Public tracker blocklists name many hosts that measure or profile visitors. squirrel’s own catalogue of vendors is curated and finite, so some hosts the lists name belong to no vendor squirrel knows. Something on your page is talking to a tracker, and the scan cannot tell you who runs it.

What squirrel checks

For each sampled page, the rule looks at requests that no catalogued vendor claims and that match one of three public lists: EasyPrivacy, uBlock Origin Privacy and uBlock Origin Badware. The lists are fetched and validated, kept as prebuilt indexes, and refreshed by a scheduled task and in the background when a copy is more than 7 days old, so an audit never waits on the lists’ servers.

• unidentified-tracker warns once per page and host. Message: https://example.com/ requests t.example-track.net, which a public tracker list names but we cannot attribute to a vendor.
• unidentified-tracker passes with No unidentified tracker was seen. otherwise.
• unidentified-tracker is skipped, never passed, when a list was unavailable or was cut short at its rule cap: Third-party scan skipped for this rule: a tracker blocklist was unavailable, so unidentified trackers could not be checked. A “none seen” with a missing list would be a guess.

A blocklist match is a heuristic. Lists are maintained by volunteers, a host may be listed for an old behaviour, and the rule does not read what the request sends. Regex-only and unsupported list rules are skipped. Only sampled pages are checked.

How to fix it

Find what loads the request: a tag, an embed, a plugin or a script a tag manager publishes. If it is something you use, add it to your privacy notice and your vendor register, and consider whether you need it. If you do not recognise it, remove it and re-run the audit.

Rule	third-party/unidentified-tracker
Category	Third-party, part of Security
Scope	Site (cloud audits only)
Severity	warning
Weight	1/10

Enable / disable

Cloud audits do not read squirrel.toml, so these rules cannot be switched off there. They run whenever the audit includes the third-party scan, and report as skipped when the scan could not run.