I recently noticed a trend of questions from various users about extracting specific bits of information such as the version of ESXi that's running or the MoRef ID of the VM, all while within the guestOS. I had already written an article about this topic awhile back called How to extract host information from within a VM? but it seems like there is still a continued interest to easily obtain this information about the underlying vSphere infrastructure from within the guestOS.
I came across another method while researching a different topic which is to use the vApp property of a VM called the OVF runtime environment. This is a feature that has been around since the early days of vSphere 4.x, if not earlier which provides a mechanism to retrieve some of this information as well as custom properties. The OVF feature provides users with the capability to pass in any type of metadata information such as application start up parameters, network configuration, password management, etc. directly into the guestOS for flexible guest customization.