>

It's not much about who's holding the debt (about 20% of US debt is foreign held, compared to 15% of Japan's debt) but on what currency is it issued. Japan, like the US, has almost all of its debt issued on its own currency. That's not common, and that's why they can get away with it.
“There are four kinds of countries: Developed countries, underdeveloped countries, Japan, and Argentina.” -Economist Simon Kuznets >

Why is Japan a standout? Is it a quote from the 80s? >

Huge amount of debt, low growth, low inflation. Yet things seem to work out. >

Because that debt is owned to their own citizens and not foreign countries. This is very common in places where there are lot of natural disasters and you need to rebuild.