To take part in manual underwriting, you'll need to provide the following information:

• History of regular housing and other payments to creditors, such as cellphone providers, utility companies and landlords
• Bank account statements to demonstrate cash savings
• Two years' worth of tax returns
• Proof of employment, such as a verification letter from your employer, that applies to the previous two years
• Prior 30 days' worth of pay stubs
• Verification of self-employment income, such as tax and other financial documentation
• Financial and credit information for a cosigner with good credit, if you have one, which could help strengthen your application

That sounds hella invasive. The banks get nowhere near as much info here unless you use a bank you already have an account in, in which case they have access to that account's information. Otherwise standard is 6 months of data.