The encyclopedia wrongfully states that command blocks will emit redstone power from their back side.

The Command Blocks page in the encyclopedia contains the following statement:

When a Command Block has either executed or failed to execute its stored command, it sends a Redstone signal from the side where the arrow is pointing.

This is false, as command blocks cannot emit Redstone power on their own, and require a comparator to be able to do so. The comparator’s output reflects the outcome of the last time the command block was run, and doesn’t exclusively emit power whenever the command block is run, and works from four different sides of the block, not just the back (the side with a circle on it).