I had to figure out when a OVA file was published (for a virtual machine). The Open Virtualization Format (OVF) is the standard for these files.

The OVF standard specifies that a OVF package consists of a folder containing files. One of them is an XML file with metadata, with extension .ovf. The others are typically components of a virtual machine, like disk images.

An OVA file (extension .ova) is a tar archive of an OVF package.

This command gives me the modified timestamp of the contained files:

And you can uze 7-zip if you want a GUI:

The .mf file contains hashes of the contained files:

This is one way to verify the hash of a contained file (the disk image, in this case):

Didier Stevens
Senior handler
Microsoft MVP
blog.DidierStevens.com