While the current state of the PR would satisfy the minimum requirement of a functional alarm board, I believe improvement is possible on the following two issues:
The JST header should be parallel to one of the main board's I2C headers, and the pins lined up so that a straight path between them is achieved, and minimal twisting of the connector is needed to join both boards
There should be an additional pin on the JST connector in order to allow for pwm of the leds. It should drive a transistor, preferrably the same used for driving the led's, in order to allow for pwm.
for alarm board