[that's just sound science, Loki.]

I don't see anything wrong with 'blue junk'.
There's not really a neat existing term for "nonphysical blue glow in your chest that gives you powers and makes you feel other peoples feelings and also randomly fetches your personal items." We can't even get cute and call it heart or something like, since it just translates.

[they used the Japanese for heart which Loki might be able to SEE but obviously it just translates.]