preferences.d
also: prefs.d, .d directory
A directory convention where configuration files for a specific application or service are stored, typically in /etc/preferences.d/ or ~/.config/app/preferences.d/, allowing modular preference management.
preferences.d directories follow the .d convention used throughout Linux systems. Rather than storing all settings in a single file, applications can split configuration into multiple files within a preferences.d subdirectory, making it easier to manage, override, and automate configuration changes.
Common locations include /etc/app/preferences.d/ for system-wide settings and ~/.config/app/preferences.d/ for user-specific preferences. Each file typically contains one logical group of settings, and files are processed in lexicographic (alphabetical) order.
For example, a mail client might have ~/.config/thunderbird/preferences.d/10-default.conf, ~/.config/thunderbird/preferences.d/20-custom.conf, and ~/.config/thunderbird/preferences.d/30-local.conf, with later files overriding earlier ones.