It's over 50MB debug info (see other comments). Release just specified the profile and you can override settings if it in Cargo.toml, e.g. to include debug inf

It's over 50MB debug info (see other comments). Release just specified the profile and you can override settings if it in Cargo.toml, e.g. to include debug info into release builds it disable lto. (Edit) which is done by the linked tool.