Is there documentation for RPi.GPIO

Is there documentation for RPi.GPIO? I have searched the web and can’t find anything.

I know I can use pydoc or help() but this produces the following:-

wait_for_edge(...)
    Wait for an edge.  Returns the channel number or None on timeout.
    channel      - either board pin number or BCM number depending on which mode is set.
    edge         - RISING, FALLING or BOTH
    [bouncetime] - time allowed between calls to allow for switchbounce
    [timeout]    - timeout in ms

This is OK, in as far as it goes, but doesn’t really explain.
I assume the function blocks until the interrupt, but this is not stated.
What are the limits/defaults for timeout?

I have the following code, which I start on boot. Pressing the button successfully shuts down, but I have noticed it also seems to shut down at other times.

I could add some code to verify the button push, or some circuitry to make it more robust, but though I would check the documentation first.

while True:
    # set an interrupt on a falling edge and wait for it to happen
    GPIO.wait_for_edge(INT, GPIO.FALLING)

    subprocess.call(['poweroff'], shell=True, 
        stdout=subprocess.PIPE, stderr=subprocess.PIPE)

Edit 2016-01-03

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I downloaded the source from SourceForge, which made things somewhat clearer, but the timeout parameter seems to be missing in action.