The jsfiddle broke, because it made lots of requests in parallel and triggered 429s. Here's the new one that does work: https://jsfiddle.net/catrope/7hfg3drv/

The defaults are as follows, but I eyeball the results and adjust where needed. For example, if the 90% precision level has a low recall (lower than 8% or so), I'll choose the 80% or 75% precision level instead. One formalism I do use: "maybe bad" is 15% precision or 90% recall, whichever of those two produces a narrower threshold range.

Change 457946 had a related patch set uploaded (by Sbisson; owner: Sbisson):
[mediawiki/extensions/Flow@master] Remove custom cache hack

I'm going to suggest that a JS error like this is most likely Beta-Cluster-reproducible, not Beta-Cluster-Infrastructure :)

I see this in the logs on opt out but it doesn't make it fail. The whole process (optin, optout, optin, reset all (optout)) works for me locally now that my vagrant is fixed.

(Should T185081 be merged into this?)

I was able to reproduce this problem on testwiki. My user talk page is corrupted.