Creating Custom Actions for VBP 8

[HippyCraig]

I found as I created a new action and compared the scripts with my previos version there appears to be a new property that I cant find information on. If I open up a build file I see the following property added to my custom action.

<buildfailsteps type='11'>0</buildfailsteps>

If I try to add exisitng actions to the same script the added actions also have this value added but the exisiting actions do not get modified when saving to have this new propery.

Can you tell me more about this and what the values represent?