So we all know that SonOff devices are basically an ESPxx device with a mains PSU and a relay. Pretty much all of the discussions of flashing include very sensible warnings about not trying to involve mains power when also connecting a 3v3 serial port and a computer all together.
It seems that the boards are well designed from a 'low voltage' electrical safety point of view, reasonable clearances and PCB cutouts, etc.
At least the TH-10 has a non-mains port (for the sensor input), so maybe it is properly double insulated.
On the SonOff Mini, I see the antenna wire comes with a 'strong electricity' warning, so I assume this is either live, or only trivially insulated.
If I add additional GPIO connections to a SonOff device, should I assume they are potentially mains potential, and treat as such (using earthed enclosure and 600V insulation), or can I safely expose these terminals for human contact?
Are all SonOff devices equal in this respect, or are some less unsafe than others (regardless of the certification, there is always some potential for failure).