Hi,
Like a lot of people here I’ve been using other people’s examples to get my own working with the new mqtt 2.4, the link below is where I started with some of this.
But if I made an educated guess the first “Shelly 1” is just a nice name for the topic, so in Habmin is see Shelly 1 under things instead of StudyShelly1, @ “Study” is just a nice location name but not sure if it has any other use.
The docs don’t really mention the use from what I’ve seen.
K