bug 1319926 included a patch to collect telemetry, but it needed to be backed out, because we ran out of buckets in JS_DEPRECATED_LANGUAGE_EXTENSIONS (bug 1331909).

Comment on attachment 9038267 [details] Data review DATA COLLECTION REVIEW RESPONSE: Is there or will there be documentation that describes the schema for the ultimate data set available publicly, complete and accurate? Yes. This collection is Telemetry so is documented in its definitions file ([Histograms.json](https://hg.mozilla.org/mozilla-central/file/tip/toolkit/components/telemetry/Histograms.json)), the [Probe Dictionary](https://telemetry.mozilla.org/probe-dictionary/), and on telemetry.mozilla.org's [Measurement Dashboards](https://telemetry.mozilla.org/new-pipeline/dist.html). Is there a control mechanism that allows the user to turn the data collection on and off? Yes. This collection is Telemetry so can be controlled through Firefox's Preferences. If the request is for permanent data collection, is there someone who will monitor the data over time? N/A, expires in Firefox 72. Using the category system of data types on the Mozilla wiki, what collection type of data do the requested measurements fall under? Category 1, Technical. Is the data collection request for default-on or default-off? Default on for prerelease channels only. Does the instrumentation include the addition of any new identifiers? No. Is the data collection covered by the existing Firefox privacy notice? Yes. Does there need to be a check-in in the future to determine whether to renew the data? Yes. :evilpie is responsible for removing or renewing the collection before it expires in Firefox 72. --- Result: datareview+

Pushed by evilpies@gmail.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/8129ef9863e5 Collect telemetry for String generics. r=arai,janerik data-review=chutten