Question: what kind of skills do financial companies typically look for from C++ devs?

Whenever I hear “C++ expert”, I don’t know what that means. Are they masters of the STL? Are they part of the “C with classes” church? Are they an unhinged template meta programmer? Are they a major gcc/clang contributor? Did they co-author a part of the language spec?

Or are they just some dude with 7 years of experience working on a single C++ codebase and the subset of features that happens to be using?