Really? I mean, to first approximation, all software engineering work is debugging. And to first approximation, all debugging is about carefully reading results and the code that generated them. That sounds pretty spot-on to my eyes.
And the variable naming quip... are you serious? One of the worst mistakes you can make when trying to read code for understanding is to rely on documentation layers like comments and variable names. Those things lie. Read the code.
I mean, obviously people do rely on those things for understanding, so when writing code it's important to have good semantically and contextually clear names for stuff (which certainly can include single letter names for local symbols repeated often!). But for debugging, you really have to train yourself to read the code, not the names.