История изменений

Из документации git archive

git archive behaves differently when given a tree ID versus when given a commit ID or tag ID. In the first case the current time is used as the modification time of each file in the archive. In the latter case the commit time as recorded in the referenced commit object is used instead. Additionally the commit ID is stored in a global extended pax header if the tar format is used; it can be extracted using git get-tar-commit-id. In ZIP files it is stored as a file comment.

И действительно, если сделать

$ git archive --prefix=newlib-2.5.0/ -o newlib-2.5.0-20170922.tar.gz newlib-snapshot-20170922
$ tar -tvzf newlib-2.5.0-20170922.tar.gz | grep include/dwarf2.h
-rw-rw-r-- root/root     12666 2017-09-19 23:36 newlib-2.5.0/include/dwarf2.h

Видимо разработчики RedHat каким-то особенным образом делали эти TarBall'ы.

Нет, судя по всему они их делали так же.

Из документации git archive

git archive behaves differently when given a tree ID versus when given a commit ID or tag ID. In the first case the current time is used as the modification time of each file in the archive. In the latter case the commit time as recorded in the referenced commit object is used instead. Additionally the commit ID is stored in a global extended pax header if the tar format is used; it can be extracted using git get-tar-commit-id. In ZIP files it is stored as a file comment.

И действительно, если сделать

$ git archive --prefix=newlib-2.5.0/ -o newlib-2.5.0-20170922.tar.gz newlib-snapshot-20170922
$ tar -tvzf newlib-2.5.0-20170922.tar.gz | grep include/dwarf2.h
-rw-rw-r-- root/root     12666 2017-09-19 23:36 newlib-2.5.0/include/dwarf2.h