Is it just me or is that schematic hard to read due to bits of text being on top of each other? Also "LED will burn when battery wrong way round" .. how about fixing this problem which you have acknowledged? What happens to your balancing resistor when you put one battery one way round?
"LED will burn when battery wrong way round" .
I don't know about the rest of it, but I think this is just an idiosyncratic translation of "LED will light when battery wrong way round" - IE it's a warning LED.
> Is it just me or is that schematic hard to read due to bits of text being on top of each other?
This is extremely common in products that are open-source community adjacent. I assume it's some sort of stylistic choice as almost none of these labels are in their default positions and many of the default text sizes have been changed, the designer has put in additional work to make this less readable.
The purple text comes from additional fields added to the symbols (specifically these look like LCSC part numbers). When adding properties there's a checkbox to choose if they're visible on the schematic or not and normally you'd leave in unchecked. Again in this case I can only assume it's some kind of stylistic choice that I don't understand as it's a common thing to see.