“This free website tracks which stocks US politicians are buying and selling... updates on a daily basis”
Correct. This part is true. The website gathers official US government trading papers and puts them into a daily list you can view for free.
Show the working
The website shown (kadoa.com/congress) aggregates public trade disclosures from the Office of the Clerk of the US House of Representatives, the US Senate Financial Disclosures database, and the Office of Government Ethics (OGE Form 278-T) on an automated, daily-updated dashboard.
Where this comes from: US House and Senate public disclosure portals via Kadoa.