It wouldn’t contain any public-domain data though. That’s the thing with LLMs, once they’re trained on data the data is gone and just added to the series of weights in the model somewhere. If it ingested something private like your tax data, it couldn’t re-create your tax data on command, that data is now gone, but if it’s seen enough private tax data it could give something that looked a lot like a tax return to someone with an untrained eye. But, a tax accountant would easily see flaws in it.
It wouldn’t contain any public-domain data though. That’s the thing with LLMs, once they’re trained on data the data is gone and just added to the series of weights in the model somewhere. If it ingested something private like your tax data, it couldn’t re-create your tax data on command, that data is now gone, but if it’s seen enough private tax data it could give something that looked a lot like a tax return to someone with an untrained eye. But, a tax accountant would easily see flaws in it.