HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hello, I'm a software engineer working with air data. For my current project, I have to work with .gbl files to generate trajectories with hysplit, but my company has been wondering whether they can generate them themselves. So, my questions are the following:
1. What do the .gbl files contain?
2. How can I open them?
3. How can they be generated?

Please see section3 of the tutorial.
https://www.ready.noaa.gov/documents/Tu ... index.html