Remove deprecated js-library-detector

[max-ostapenko]

Was part of the legacy repo: HTTPArchive/legacy.httparchive.org#85

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[tunetheweb]

Let's go one step further and remove the library from third-parties.js custom-metric.

It looks like this was added in April 2017 but then a year later in March 2018 Wappalyzer support was added. As that's our preferred detection library and since lib-detector hasn't been updated in 5 years it's value is questionable. Let's ditch it completely.

However, as third-party is a custom-metric column, we still need to return this I presume? So maybe return a blank value for now and we can enhance it later (maybe with some almanac custom metric code if any third-party code in there - not checked)

[tunetheweb]

FYI @pmeenan

[tunetheweb]

Oh I also discovered that Lighthouse uses this library: https://github.com/search?q=repo%3AGoogleChrome%2Flighthouse+js-library-detector&type=code

And it appears there are newer versions and some activity on the repo: https://github.com/johnmichel/Library-Detector-for-Chrome/commits/main/

But I still vote to remove it since: 1) Wappalyzer is our preferred detection library and 2) We get all it gives in Lighthouse anyway! and 3) One less thing to manage (and forget to update for 5 years!)

[github-actions]

https://almanac.httparchive.org/en/2022/

WPT result details

Changed custom metrics values:

{
  "_third-parties": null
}

[max-ostapenko]

And Almanac 3P chapter actually uses another source based on https://github.com/patrickhulce/third-party-web

P.S. Here are the detected libraries in case we'd try to match the detections in Wappalyzer:

SELECT
  SAFE.STRING(third_party.name) AS name,
  COUNT(DISTINCT page) AS count_of_pages
FROM httparchive.crawl.pages,
  UNNEST(JSON_QUERY_ARRAY(custom_metrics.third_parties)) AS third_party
WHERE
  date = '2025-12-01' AND
  custom_metrics.third_parties IS NOT NULL
GROUP BY name
ORDER BY count_of_pages DESC

[tunetheweb]

Thanks!