These are series protection resistors on the I2C lines. SDA and SCL drivers are open-drain outputs, requiring a pullup resistor to generate a logic-high voltage. Series resistors RS are optional. These series resistors protect the input stages of the device from high-voltage spikes on the bus lines, and minimize crosstalk and undershoot of the bus signals.
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https://electronics.stackexchange.com/questions/191866/series-protection-resistors-on-i2c-lines