The suffix .txt indicates a simple data storage format. In the context of third-party tools, "Fresh" usually denotes one of two things:

Unofficial Valorant documentation and tools for third party developers

Unofficial documentation often details how these scripts interact with Riot’s local and remote endpoints to verify account status. 4. Security Risks and Countermeasures

Riot’s API endpoints are heavily rate-limited to prevent the mass credential stuffing required to populate a "fresh" list.