The other thing besides the autoconf soup is the XZ project contains incomprehensible binaries as "test data"; the "bad-3-corrupt_lzma2.xz" part of the backdo

The other thing besides the autoconf soup is the XZ project contains incomprehensible binaries as "test data"; the "bad-3-corrupt_lzma2.xz" part of the backdoor that they even put in the repo. It's entirely possible they could have got that injection through review, even if they had that framwork and instead put it in source files used to generate autoconf soup.