Most debugging informations are "useless" until they are desparately needed, and this "wasted space" was no exception. So as always, it's another trade-off: will you "waste" some bytes to ease yourself in the future? Cargo already has decided that uninformed people don't want them for the release mode, but it was found that this decision was not uniformly enforced and some debuginfo was still left there. So a new option was added and the default was changed. Happy ending!