Configuration written to $XDG_CONFIG_HOME/keepassxc/keepassxc.ini.
See https://github.com/keepassxreboot/keepassxc/blob/develop/src/core/Config.cpp for the full list of options.
When the settings are non-empty, the configuration file will be linked into the Nix store and KeePassXC will report an access error for its configuration file. This is expected and can not be fixed in a way that aligns with Home Manager's principles. See #8257 for more details.