A CAN device that uses 11-bit identifiers is commonly called CAN 2.0A and a CAN device that uses 29-bit identifiers is commonly called CAN 2.0B. These standards are freely available from Bosch along with other specifications and white papers.
Standards are written by committees, funded in part by tax payer - country dependent - To fund the people who hopefully write unbiased common sense standards - they charge for the privilege of owning a copy.
Some technical standards present a trade barrier to lesser developed nations.
Interpreting a standard often calls for a good deal of technical experience in that same field.