Whether a build is debug or release is independent of whether it contains debug symbols. Both `cargo build` and `cargo build --release` produce builds with debug symbols.
Oh, you may be right. My company's main codebase does indeed have that; I had assumed it was the default.
I think you still get symbols for libstd without that. I can see why that would lead to confusion - stripping a plain --release build still saves a few MB.
IIRC this is correct, libstd is built in release mode but with debuginfo.