After updating to Unity 6.3, I noticed that all of the NuGet UPM packages are being flagged as unsigned (see screenshot below). The Unity Manual has instructions for exporting/signing a UPM package. Looks like the main thing needed is a Unity Cloud Organization to associate with the package, and then run the Editor from the CLI with -upmPack.

After updating to Unity 6.3, I noticed that all of the NuGet UPM packages are being flagged as unsigned (see screenshot below). The Unity Manual has instructions for exporting/signing a UPM package. Looks like the main thing needed is a Unity Cloud Organization to associate with the package, and then run the Editor from the CLI with
-upmPack.