VMware Virtual Appliances (VA) that are built from either VMware or from our 3rd party eco-system will typically include useful metadata about the solution including name, version, vendor and other details.
Using the vSphere UI, you can locate this information when selecting a VM under Configure->Settings->vApp Options and below is an example for a vCenter Server Appliance (VCSA).
Note: If you deploy a VA directly to an ESXi host, these VA properties will not be available as the vApp capability is a vCenter Server feature.
I recently had an inquiry from a customer with over 10K+ VMs that was looking to identify this information and obviously, using the vSphere UI would be a non-starter and was looking for a way to automate this.