NetworkManager supports various plugins, which can define new storage locations for configuration information. The currently enabled plugins can be found in
The generic default plugin is
keyfile, which stores configurations in
/etc/NetworkManager/system-connections directory, in files similar to Windows
Other plugins may be distribution-specific:
Fedora and RedHat use
ifcfg-rh, which will both read and write
Debian and Ubuntu use
ifupdown, which is a read-only plugin: it reads
/etc/network/interfaces but does not make any changes to it. Any configuration changes you make through NetworkManager will be saved using the
keyfile plugin instead.
SuSE apparently used to have
ifcfg-suse, but it seems to be deprecated.
Other distributions may have their own plugins.
Having said that, the
802-11-wireless.band setting probably gets its default value from the WiFi NIC capabilities reported by the driver. It would be saved only if you wanted to explicitly restrict the NIC to only some types of WiFi networking.
If your WiFi NIC can only transmit in the 2.4 GHz band, you cannot add
ac capabilities by just reconfiguring the software or the driver: it would require a new radio module and a new antenna tuned for the 5.0 GHz band.