A file in place whose contents differ (another revision, a personal
dump) was overwritten and lost. It is now moved to
retrobios-backup/<date-time>/ beside the folder written to, under the
same path, before the verified copy replaces it. Beside, not inside:
DuckStation, SwanStation and Rustation read every file of the BIOS
folder and BizHawk walks its firmware folder recursively.
Identical files are never kept. --dry-run counts what would be kept,
the summary and the summary event name the folder, files and bytes,
and --restore FOLDER puts the files back. Data trees and standalone
copies keep their replaced files the same way.
device_group in the registry places each platform on the device picker, in the navigation and on the home page. scripts/siteguides.py holds the guide text per platform: what it is, its BIOS folder, where the install command runs.