What is the difference between raw.hbs handlerbar files and only .hbs handlerbar files?

In some recent work, I’ve needed some of the template “tree” to be able to communicate data up from a leaf template using closure actions, so I’ve switched some of the hbr’s to hbs’s to support his.

The work is experimental and I appreciate this will have a performance impact, but after iterating the design a few times was unable to find an alternative way of doing this whilst keeping “in-framework”.