Earlier quoted context omitted.
I've built quite a lot with what I've learned, however it's not always possible to demonstrate that. Consider that I am not permitted to tell anyone at all what my most-recent project was, other than that it had something to do with OpenGL. This because the product was an in-house tool for a client of my client. The very existence of that tool is a closely guarded trade secret. I read Robert Ward's excellent "Debuggi…
As a side note - I wish more interviewers would ask debugging related questions. I had a couple coworkers at Google who would try them ("Here's some code with some bugs in it. Identify them, or talk me through how you would identify them"), but they were definitely in the minority. Debugging is its own skill, very different from writing green-field code, and yet a large portion of the time we spend as professional so…
Now some of that is adding features but much of it is fixing bugs.
I work very very hard to promote myself as a debugging specialist, but it is quite uncommon for potential employers to even care.
The most common requirement for "Debug" - not "Debugging" just "Debug" - is for really low-level embedded work. Not even kernel nor device driver work, stuff like board bring-up.
However I have gotten a few jobs specifically as a debugger. My very first retail coding job got me the title of "Product Development Manager", but in reality I was hired to debug a product that my predecessor made a smoking crater of. I've also been a "Debug Meister" for Apple, and a "Man in Black" for Sony Ericsson Mobile Communications, where I worked on what is now the Sony Mobile XPeria Play.