Resistor parallel to an LED?
The resistors are there to make sure that the pin is pulled all the way to ground when the LED is off.

This is important, for example, when you are using RMW (read-modify-write) operations to toggle individual LEDs. When you read all 8 pins, the LEDs that are supposed to be off could still read as "1" because of the forward voltage of the LED. When you write the byte out again, those LEDs will now turn on, even though that isn't what was intended.

There are other ways to avoid this problem, but including the resistors follows the principle of "least surprise" &mdash; especially for the newbies who are likely to be using such a board.

A parallel resistor is more commonly seen when you want to use an LED as both a pull-up and an indicator, but it makes sense in this configuration, too.