Whilst looking for something else entirely, i stumbled across these, in Chrome's Application Support folder.
# syh @ h in ~/Library/Application Support/Google/Chrome/ZxcvbnData/1 [21:07:42]
$ l
total 1592
drwx------@ 11 syh staff 352B Dec 19 21:06 .
drwx------@ 3 syh staff 96B Dec 19 21:06 ..
-rw-r--r--@ 1 syh staff 66B Oct 11 10:56 manifest.fingerprint
drwx------@ 3 syh staff 96B Oct 11 10:56 _metadata
-rw-------@ 1 syh staff 166B Oct 11 10:56 manifest.json
-rw-------@ 1 syh staff 271K Oct 11 10:56 english_wikipedia.txt
-rw-------@ 1 syh staff 26K Oct 11 10:56 female_names.txt
-rw-------@ 1 syh staff 6.5K Oct 11 10:56 male_names.txt
-rw-------@ 1 syh staff 236K Oct 11 10:56 passwords.txt
-rw-------@ 1 syh staff 74K Oct 11 10:56 surnames.txt
-rw-------@ 1 syh staff 160K Oct 11 10:56 us_tv_and_film.txt
It looks like some data that is being used by zxcvbn, which Chrome might be using. Does anyone know what Chrome is using this for?
This was tracked in Chromium bug 1104878 - Passwords: Add zxcvbn-cpp as third_party library.
This issue serves as a tracking bug to add zxcvbn-cpp [1] as a third_party library to Chromium. It is intended to be used for realistic password strength estimation within the Password Manager component.