Disclaimer: Sidecard files are an improvement over the old centralized history. Please just ignore them on your file explorer and everything will be great. You can
try to modify the code and return to the old behaviour but expect some broken stuff.
Storage candidates for docsettings:
https://github.com/koreader/koreader....lua#L113-L125.
Please remember if you use the "old" history file that all the books are expected to be on the same path always or you'll miss the progress (like when you remove a sidecar file)
Also I'm not sure but probably the history file will grow with junk stuff if you try to "refactor" your folder structure or if you remove a bunch of books or ...