I actually like the K3 default sans serif font except I would like to make it bold. Currently I use calibre to change the CSS by adding body { font-weight: bold; }.

But since the font hack now works on the K3, changing this to the bold font would be great and would save me from a lot of conversions, but I cannot figure out what the font is. It is not HelveticaNeue 65 LT Medium; though close there are some differences.

So has anyone positively identified the default sans serif font?