Ask HN: Question about giving repo access for Tech Due Diligence for Seed

My startup is (i think) near closing a seed round. As part of that the investor is requesting tech due diligence, fine and expected. One thing caught me off-guard and is wondering if it's the norm or not. and if so, what is the standard way as a company we should handle this.

Their ask is for access to key code repositories across backend, api, and mobile. Even before the DD session. My gut is that kind of access would make sense if there was a contractual "Term Sheet Contingent on XYZ".

Something just sits wrong with me, so I ask HN,am i overthinking this, or is that normal?