Are VPNs(65528, 65529, 65530) reserved only for loopback inerfaces?

[svemulap@cisco.com · Accepted solution]

These VPNs are actually Reserved ones.

VPN 65528: For Umbrella / Zscaler
VPN 65529: For Speed Test
VPN 65530: For SIG_Tracker [ Layer 7 Health Check Probes ]

When they are in use, a loopback is associated to those.

You can find more info. on Cisco documentation.
Eg.: Layer 7 health check at:
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-zscaler-206-deploy-guide.html?dtid=osscdc000283#Layer7HealthCheckforAutoTunnels

HTH