Acknowledgements
Daphne Preston-Kendal devised the string notation for bytevectors; John Cowan, the procedure library; Wolfgang Corcoran-Mathe, the original, sample implementation of the procedures.
The notation is inspired by the notation used in Python since version 2.6 for bytes objects, which are fundamentally similar in purpose to Scheme bytevectors, especially in R7RS. In addition, many of the procedures are closely analogous to those of SRFI 152.
Thanks is also due to the participants in the SRFI mailing list. In particular: Lassi Kortela corrected an embarrassing technical error; Marc Nieper-Wißkirchen explained why the write procedure ought not to be allowed to use this notation by default.