Whether the network is considered metered. That is, whether the system has traffic flowing through the default connection that is subject to limitations set by service providers. For example, traffic might be billed by the amount of data transmitted, or there might be a quota on the amount of traffic per month. This is typical with tethered connections (3G and 4G) and in such situations, bandwidth intensive applications may wish to avoid network activity where possible if it will cost the user money or use up their limited quota.
If more information is required about specific devices then the system network management API should be used instead (for example, NetworkManager or ConnMan).
If this information is not available then no networks will be marked as metered.