For starters, 240VAC input represented by what appears to be a vanilla barrel jack; PCB relay module that doesn't look like it'd come close to meeting clearance, creepage, etc requirements expected of such applications; wiring represented as discrete point-to-point while completely ignoring the importance of gauge, insulation rating, etc. I just hope an ignorant passerby doesn't try to hack this up with speaker wire and arbitrary AliExpress relay module thinking the relays are rated for 240VAC so it must be OK (when everything else wasn't designed for such high voltage application).
All valid points, the beauty of Github is that you can write a pull request and add all those informations to the project, or even better, you can write what an alternative solution would be 'Instead of using X, you can use Y'. If you feel extreme generous you could even use this as a teaching opportunity. Explain concept like Creepage starting from the existing example and propose the alternative solution from there.
A PR would be great actually. Open source projects are amazing and more people can use it safe. Or you can share here the improvements and will modify it myself.
It's a Fritzing diagram, which is to say it's a schematic, not a layout. So the thickness of lines should not be taken as indicative of any physical properties like connector style, wire gauge, or insulation. Clearance and creepage are concerns for PCB designers, but there doesn't seem to be any custom PCB layout and design work here - why mention it?
