How does insurance/lenders know about issues.

I keep running into houses with issues.

For example. Yesterday’s has a rotted oil tank in the basement that has a slow drip.

It also has a federal pacific breaker panel which was deemed to not be to code and a fire hazard.

I read online that insurance companies or even brokers can deny a mortgage or coverage for these issues.

Sorry if it’s a stupid question, but how would they know? Insurance doesn’t look inside your house. The lender i think gets a property disclosure from the seller. So if it’s listed there I can understand that.

But let’s say for example I agree with seller on a credit to fix the issues. Do I risk a mortgage approval or an insurance denial?

I would imagine if I request the credit for these issues, the seller is going to put it in the contract to cover themselves. But then again, won’t that notify the lender and insurance?