I recently found software containing only binaries (no access to source code) being distributed and dual-licensed under the GPL3 (https://www.gnu.org/licenses/gpl-3.0.en.html) and MIT (https://opensource.org/licenses/MIT).
These two licenses tend to be applied to open-source software, so I am wondering whether it is legal to apply either of them to closed-source software (program executables/binaries, also referred to as object-code) without being obligated to provide the source code?
It is worth noting that the question is related to the original creator of the software applying the license to their own work, not someone creating a 'fork' of a work that is already distributed with one of these licenses.