I'm also very curious how this can work. For example: I have always used a (very) old actionreplay plugin with a .plg extension. You could simply have a TitleID folder with cheats.txt and the plugin.plg file and you are good to go. I believe it used the
CTRPluginFramework v.3.0.0. Currently with the latest 10.2.1 firmware only .3gx files can be loaded.
If there is a way to either convert a .plg to .3gx or cheat.txt file to .3gx so it can be loaded using the new
CTRPluginFramework v.6.0.0 that would be nice.
The only .3gx I could find is: file
https://gbatemp.net/threads/release-mario-kart-7-online-ntr-plugin.460631/ if there are more please post them