[iamthepieman]

I agree. I've had this happen often enough on the job that it's not a totally made up example. And usually you'll be one of two or three people in the whole company who is able and willing.

Debugging old DSL vendor specific languages or code so old using, frameworks and standards long out of fashion and support, that they are half way to being a different language.

Adding support for some back ported features or patching security holes in an old client or legacy stacks.

Or at a big company we had some escrow code from a much smaller partner that we ended up becoming responsible for.

Often getting the environment setup for proper debugging is more work than anything.

But yes, it's a good test for a senior+.