The transfer of the keys on GNOME Keysign was limited to the LAN only. This limitation can be a problem when e.g. one user does not have access to a WIFI/Ethernet connection or when the users are connected to an isolated network (like a guest WIFI or an University Intranet).
The goal was to further facilitate the OpenPGP keys signing process on GNOME Keysign. This was achieved by adding the ability to send the keys using Bluetooth and Magic Wormhole. The first allows two near PCs to communicate even if there is no LAN/WAN connectivity; The second allows the communication when two PCs are in a LAN (or isolated LAN) or located remotely.
As of August 2018 both Magic Wormhole and Bluetooth functionality are merged upstream. These were the relative pull requests:
gnome-keysign/gnome-keysign#15 replaced with gnome-keysign/gnome-keysign#31
gnome-keysign/gnome-keysign#18
The following are my blog posts about the progress I made:
https://ryuzakikk.github.io/gnome/initial-wormhole-implementation/
https://ryuzakikk.github.io/gnome/wormhole-improvements/
https://ryuzakikk.github.io/gnome/wormhole-refinements-and-bluetooth/