I am very glad to discover the new Stdlib.{In_,Out_}channel introduced in OCaml 4.14. Thank you, folks!
Sorry for my remark that is purely bikeshedding, but I had the impression that camel case was usually preferred for naming modules. It is the case for instance for all the standard library modules except these two new ones (and, in particular, it is worth noticing we have BytesLabel, StringLabel, etc.). I am afraid we are going to lose one of the few naming conventions we have with this change.
I understand that the choice was to mirror in_channel and out_channel type names, but one can say that mirroring snake case for type names with camel case for module names is equally valid. Does the choice between {In_,Out_}channel and {In,Out}Channel have been discussed before?