would assume they doing some rudimentary automated checks for reasonable expenses like where your address is etc.
If you earn 10k a year but have an address in mayfair. it might trigger something.
The Inflation Reduction Act (IRA) of 2022 gives the IRS $80 billion over ten years to hire up to 87,000 new IRS employees, largely to increase the number of tax audits. Individuals making under $400k per year are not supposed to get extra scrutiny; emphasis will be on high earners, large corporations, and partnerships.