There were two major issues with the previous implementation:
* The exported folder name was localised so it was "Files" or "Soubory"
etc depending on the current language. Yet URLs referring to the files
in that folder were always rewritten with hard-coded English "files".
* Files from all fileareas and itemids were all exported to a single
target directory. So if there were two files with the same name being
exported from multiple areas (such as submission_content and
submission_attachment in the workshop module), one would overwrite
another.
The patch addresses these issues as follows:
* To unify the folder name and also to minimise the risk of conflict
with a subcontext folder, we now always export stored files under
"_files" folder.
* Under that folder, there is a subdirectory with the area name and then
eventually another subdirectory with non-zero itemid. And there
finally the stored_file is exported to under its own file path.
Eloy Lafuente (stronk7)