Tarball dumps are OK. The GPL doesn't require change history. Although it can be quite helpful, it would be quite hard to define universally - what level of history is required? It could range from "every character typed" to "changes from the last public release", which is essentially what we have now.

GPL requires source code, which it defines as "the preferred form of the work for making modifications to it."

This prevents release of compilable-but-obfuscated code, or transpiler output, etc., or intentional removal of information required to build the software (though this clause causes GPL-compatibility issues with authenticated-build platforms).