This allows you to manually set the individual sensors in your home. You can change the mode for that sensor independently. For example, instead of arming the whole house, you can arm just a few sensors. You can also change the 'Bypass' setting for each sensor. 'Normal' means the sensor is not bypassed. 'Wait' means the sensor is waiting however many seconds you specified in the 'Wait before alarm' setting before becoming active. It will return to 'Normal' after that many seconds. 'Bypass' means you have bypassed this sensor this one time. As soon as someone enters the PIN code on Orbiter the sensor will not be bypassed anymore. 'Perm bypass' means the sensor is bypassed and will stay bypassed until you change it again here on this page.
If you want to permanently disable a certain sensor, you could go to the Wizard/Security/Respond to Sensors page and change that sensor to "Do nothing". That allows you to disable the sensor for only certain modes (like armed or sleeping). Or you can set it to "Perm bypass" on this page. That means the sensor is permanently bypassed for all modes no matter what you put on the Respond to Sensors page.