automate layer movement

[gimpygirl]

Thanks a lot!
I think a new hobby has started!

•  Are there website that provide free scripts/plugins for GIMP (like a collection of scripts people made and share)? Or does this not exist?
  
• what website do you recommend for learning about scripting and plugins (complete beginners)? Maybe there is a free ebook released?
  
• Should I learn scripting or to make a plugin: what is the most usable and maybe best for a beginner?
  
• this is official API? https://developer.gimp.org/api/2.0/libgimp/
  
• some questions about the example script
  

1. where does "pdb" come from?
   
2. "timg" means the full image?
   
3. how do you know the exact name of script/plugin to use in the code like "script_fu_grid_guides" and "python_fu_ofn_guillotine_layer" ? It seems it startswith "script_fu" or "python_fu" always but where to find the exact name?
   
4. what is a "tdrawable"?