libcbor is, generally speaking, very faithful implementation of RFC 7049. There are, however, some limitations imposed by technical constraints.
There is no explicit limitation of indefinite length byte strings.  libcbor will not handle byte strings with more chunks than the maximum value of
size_t. On any sane platform, such string would not fit in the memory anyway. It is, however, possible to process arbitrarily long strings and byte strings using the streaming decoder.
“Half-precision” IEEE 754 floats¶
As of C99 and even C11, there is no standard implementation for 2 bytes floats. libcbor packs them as a
double. When encoding, libcbor selects the appropriate wire representation based on metadata and the actual value. This applies both to canonical and normal mode.