Microsoft does not provides much information about these logs. You can see the type of logs mentioned here but nothing besides just being mentioned. As the gateways are are probably build upon Windows Server VPN features probably these logs are similar to the ones available on server. The logs are only for point-to-point connection which means only when using clients to connect to the Azure Network Gateway (VPN). My conclusion is that these logs are more of diagnostic logs in case you have some problems so you can troubleshoot but cannot be used for monitoring. Logs like TunnelDiagnosticLog and GatewayDiagnosticLog are more suitable as they contain more information and better structured.
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