You are using staging server - a separate instance of the ESP Component Registry that allows you to try distribution tools and processes without affecting the real registry.
# Component: MPU6050 * C driver for MPU6050 gyroscope and accelerometer. * See [datasheet](https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-6000-Datasheet1.pdf).
idf.py add-dependency "espressif/mpu6050^1.0.0-alpha"