% Answers for galley proofs: \ansno X.0: According to the index, |\|\] is primitive but |\|\<return> isn't. The command `|\def\↑↑M{\ }|' in Appendix~B is what actually defines |\|\<return>, since a return is representable as |↑↑M|. Asking \TeX\ to |\show\↑↑M| \looseness-1 produces the response `|>| |\↑↑M=macro:->\|\]|.|'.