I’d be blown away if this is the case. Credit models are carefully guarded. They’re also expensive to run. If Credit Karma could approximate the pricey model with open-source data, they’d have been bought by a bank, not a tax company.
Also, Intuit is much more than a tax company now.
There are a lot of people doing this. For the aforementioned reason: a cheap approximation of a credit score is valuable. Before the financial crisis, VantageScore was developed by the credit bureaus to disintermediate Fair Isaac. This work continues, and Credit Karma is far from unique in its approach or data.
That’s a different problem than simply evaluating credit risk, and is much less researched — so not the same as the highly guarded credit models.