gupd notes
 

gupd files are a good way to package files and let it automatically download on login. But please make sure that you specify the good path for files: they must match the path where it would download them by default (we can may be let it ignore the path in the future, but right now please specify the good path):

Images starting with something_ must be put in levels/images/something/:
levels/images/era/era_*

Heads, shields etc. in their levels folder:
levels/heads/*

Well that's just like, your opinion Stefan.

This is kindof complicated when you have files like "classic_head_originalbaddy_red.png" and you're placing it in a folder "levels/gifs/protected", and you then have a system which scans all files within the folder "protected", checks for new files being added to it via onLevelFileUpdated(), and creates a hash that prevents graphic uploads of the same filenames.

And what about GUPDs containing gmaps?
Iirc files can't be downloaded when outside the levels/ folder, so they couldn't be put in maps/.

Gmaps are put in the maps folder. I think it can also be possible to not specify any path, but would need to test if first.
The problem is that on login to servers like Era it's downloading some files at each login because it's storing the files in the wrong path.

This happens on Graal the Adventure every time I log on, it downloads the music pack.

Music files are located within levels/music/, which seems to be where they should be.

I've also noticed this type of behaviour when using a scripted pre-loader via fileexists() and fileupdate(), for stuff such as seasonal images.