Each fault has at least three lines in the .pro file. The first line begins with the word fault: and the name of the gate node of the fault, such as bb_99. Next comes lists of nodes which are affected by the fault, the first on the same line with the gate node. Each list appears on a separate line that begins with the type of fault that affects the nodes, such as brg: or brk:. See the Explanation of Faults chapter for more on the meaning of these lists. Transistor gate bridge/breaks will have two different types of lists, one for the bridges and one the breaks. Next comes a line with the rank, relative probability of the fault, and the total critical area of the fault.
After that, there are one or more lines breaking down the total likelihood of occurrence for the fault by the layers of material causing the fault. These lines begin with the word layer: followed by the name of the layers that contain the fault and the percentages, shown as decimal values. The given layer's contribution to the critical area is followed by the actual computed critical area on the given layer(s).
Comment lines can appear anywhere in the file. These lines will always have a # symbol at the beginning of the line.