- Removed Devuan testing-security repositories from all sources.list files
- Removed Devuan security mirror references from main config
- Changed all instances of 'firmware-nonfree' to 'non-free-firmware'
- Updated preseed to use correct non-free-firmware component name
- Updated apt preferences to remove Devuan security references
- Maintains Debian security updates while removing Devuan security repos
- Ensures consistent naming convention across all configuration files