[T]he initial portion doesn't mean the first line, it means the script part of a file consisting of a shell script and a binary payload, separated by `exit', `e

[T]he initial portion doesn't mean the first line, it means the script part of a file consisting of a shell script and a binary payload, separated by `exit', `exec whatever', etc. A good example is the Oracle Developer Studio installation script. You can write to Austin Group mailing list and ask for clarification if you want.