what are ".start" and ".target" files in the GPU accelerated path tracking example script

[C-H-Chien]

Hi, I planned to use the GPU accelerated path tracking python example script as shown in this link.

However, I was unable to use it because I find neither .target nor .start files from the whole PHCpack folder. I tried to find the format inside those two files but was also failed to find it.

Thanks in advance!