Identifying how this switch with indicator light is wired
Ok. So the indicator lamp is on when the light is on.   And if either your or the neighbor switch the light on, it's on.     This is unusual, but workable, and your description in your comment makes it all fit together.  

The location of the pins on the switch/lamp is what gave me pause.  

The switch and lamp are totally separate. They don't even have tabs to break off.   

The cable coming from the other switch goes to your switch.   It carries hot and switched-hot.   It is wired in parallel with your neighbor's switch.  Your switch's two terminals go to the same place as your neighbor's switch's two terminals.    Eiher your switch or your neighbor's can give current a path to the light.   

The cable coming from the light goes to your indicator lamp.  It is in parallel with the lamp, so the indicator gets power when the lamp gets power.  The two wires are switched-hot and neutral.   

What struck me is it's a little bit wasteful.  The switched-hot is logically the same wire on both the switch and the lamp and could have been done with a single  /3 cable.  

But this method is also alright, it's visibly obvious what is happening from how the cables are routed, so you don't have to logick it out.