To use RMaker.h , you must download the full library.
After downloading the official ZIP, compare the SHA-256 hash.
The RMaker.h file is a core header for , an end-to-end IoT solution by Espressif designed specifically for the ESP32 series . It is not a standalone library you typically download as a single ZIP from a generic site; rather, it is integrated into the official Espressif Arduino ESP32 core . How to Download and Install