Adsads.txt is an open standard and technical specification defining how a publisher can publicly declare their list of “Authorized Digital Sellers,” in an “ads.txt” on their site. It is a mechanism for publishers to list their authorized digital sellers in order to fight against fraud and misrepresented domains. Developed by the IAB Tech Lab, it's a simple, flexible, and secure way for content owners and distributors to declare who is authorized to sell their inventory, improving transparency for programmatic buyers.
App-ads.txt extends extends ads.txt functionality to include inventory from mobile apps and over-the-top (OTT) video. The new app-ads.txt specification relies on the publisher URL, available on app store HTML pages, as the centrally located, crawler-friendly, trusted source. meet the requirements for applications distributed through mobile app stores, connected television app stores, or other application distribution channels.
Learn more about ads.txt and app-ads.txt: