请哪位能提供PCB ASCII FILE 6 VERSION 2.80的详细说明？

请哪位能提供PCB ASCII FILE 6 VERSION 2.80的详细说明？先谢谢！

文件内容如下：
PCB FILE 6 VERSION 2.80
0 20 0 0 0 0 0 0 2 4
FS
0 0 7200000 3200000 60000 0.000 0 1 33 0 0 0 0 10000 1 0 0
.LEGEND
FS
0 0 7200000 3100000 60000 0.000 0 1 33 0 0 0 0 10000 1 0 0
Drill Drawing.
FT
0 0 2050000 3050000 6950000 3050000 10000 28 0 0 0
?0 0 1 0 0
FT
0 0 6950000 3050000 6950000 6950000 10000 28 0 0 0
?0 0 1 0 0
FT
0 0 2050000 6950000 6950000 6950000 10000 28 0 0 0
?0 0 1 0 0
FT
0 0 2050000 3050000 2050000 6950000 10000 28 0 0 0
?0 0 1 0 0
FT
0 0 6950000 2720000 6950000 3035000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 2050000 2720000 2050000 3035000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 4849886 2730000 6950000 2730000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 2050000 2730000 4118113 2730000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 6890000 2750000 6950000 2730000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 6890000 2710000 6950000 2730000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 2050000 2730000 2110000 2710000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 2050000 2730000 2110000 2750000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1590000 6950000 2035000 6950000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1590000 3050000 2035000 3050000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1600000 5349886 1600000 6950000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1600000 3050000 1600000 4618113 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1580000 6890000 1600000 6950000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1600000 6950000 1620000 6890000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1600000 3050000 1620000 3110000 10000 29 0 0 0
?0 0 1 0 0
FT
0 0 1580000 3110000 1600000 3050000 10000 29 0 0 0
?0 0 1 0 0
FP
0 0 3360000 5165000 137795 137795 1 137795 137795 1 137795 137795 1 137795 0 34 0 0 0.000 4000 0 10000 10000 20000 4 1 1 1 1 1 1 1 1
0
FP
0 0 4385000 5150000 137795 137795 1 137795 137795 1 137795 137795 1 137795 0 34 0 0 0.000 4000 0 10000 10000 20000 4 1 1 1 1 1 1 1 1
1