This is really directed towards Dan, since I suspect he's the only one with answers. :-)
In the py3 branch, it seems that the intent for live mode radios is to change the behaviour so that they act more like clone mode. That is, instead of changes being sent to the radio as soon as they're made, as with today's Chirp, nothing is sent to the radio until an Upload is done. I presume this was done to make the two modes appear more consistent. (It's confusing to existing users who expect instant changes, though, and will require clear documentation.)
As part of the implementation, a LiveAdapter class is used, and that is a subclass of the Generic CSV driver. I'm guessing is that this is intended to enable the saving and loading of "images" for live mode radios, using CSV files as the file backing. After downloading from a live mode radio, saving does work, and produces a CSV file, but with a file extension of "img" rather than "csv". Due to that file extension, however, loading does _not_ work, because the image type detection code does not look for CSV-typed data.
Also, immediately after a Download, the tab in the GUI shows a ".img" filename, and shows it as edited. It's unclear as to whether this is intended (because no file has been saved) or not (because no changes have actually been made to the memories that were just downloaded).
Finally (for now), when running an Upload, all memories are written to the radio, regardless of whether or not they have been changed. This can be slow, since all memories in all banks are written. If I Download from the radio, change one memory, and then Upload to the radio, because of the way live mode radios work, it seems like it would make more sense to upload only the memory that has changed. This may get more complicated when dealing with "images" loaded from a file, though - or maybe not, since memories are also being read as they are being written.
Before I dive in and look at making changes, it would be helpful to understand the thinking behind the approach, and the intent of how it should work, particularly in regard to the points mentioned above, but also in any other related regard. I do have a local change for writing only changed memories, but I'd like to have the big picture before going any further.
Thanks,
Martin. KD6YAM