How to set kint() to be closed by default? I find that when expanding Kint widgets, if the object is sufficiently large, the loading time can be quite slow. It appears, when you expand the root level, it also expands child objects. I would prefer that it keeps all children closed until I decide to expand; although I'm not sure if this will have any impact on performance.

Where can I configure Kint for Drupal?
I know this is an old question, but I just figured this out and this question comes up first on google.  

The option is already there. What you need to do is click next to the plus sign (the text next to it) not the actual plus sign itself. Clicking the plus sign will expand everything, clicking the title, path or array key will just expand the immediate node below it. 

I went through almost a whole project thinking Kint() unusable when it's really just a confusing UI choice.