The "suffix" there is a docs mistake. if you look at the example csexp's on the page the lengths are prefixed. I think that the csexp's of this package are compatible with Rivest's format.
With netstrings, it's
3:bag,
with a comma, which makes it a bit more readable over the wire.The extra level of Racket quoting was confusing me -- #"" and \" -- it would be nicer if they just wrote exactly what's transmitted over the wire.
And still the page does seem like it's missing a reference. Both Rivest's page and this page seem a bit underdeveloped for a "canonical" format ...
Namely interoperability between Lisps