how to get stuff out from a *.wpress file?

The .*wpress isn’t just a zip file. That feels like an undesirable/unneeded lock-in to users, especially if we’d need to access specific files inside a given archive, w/o restoring the whole thing first. All other similar plugins tested used just a zip.

Would you please tell how to open a *.wpress file, and be able to retrieve files from it, w/o a full restore?

Thanks.