Native Dev Rig - Opening an project

Hi. Wanted to try out the native dev rig since they released the 1.0.2 version.
However, I’m unable to open any of my old projects that works fine under the locally hosted dev rig. I still haven’t figured out what JSON file I’m suppose to open, but I did try to copy the response you get after using the “refresh manifest” button in the old dev rig. Unfortunately this did not work and only yielded an error saying “Cannot open /user/user/desktop/file.json: Cannot read property of ‘id’ of undefined”, even tho there is a key called id which has a string value.

So what am I suppose to do to open either an released version of the extension or a version I’m working on?

Edit: should also mention I’ve only tried the ‘Native dev rig’ on Mac, running High Sierra 10.13.6

Edit 2: Tested on Windows 10 as well, still the same problem.

The project concept in the old Developer Rig was realized in the browser’s local storage. In the new Developer Rig, it is realized as JSON file in the project folder. An extension manifest, as provided in the response to the API the “refresh manifest” button invokes, is not a Developer rig project. Your best option with the new Developer Rig is to create a new project, selecting your extension from the “Select Existing or Create New Extension” drop-down list and entering your desired version in the “Extension Version” input.

Alright, guess I’ll have to wait until the next version of the extension to use the new dev rig, thx!