The Business Architecture Core Metamodel (BACM) is issued by the OMG as a beta specification
The work on this specification began in 2017 and the beta specification is published on the Object Management Group site, omg.org on the adopted specifications page. The purpose of a beta specification is to allow implementers and users of the specification to discover and correct flaws in the beta specification, leading to the publication of a final specification. The OMG specification finalization process is open to anyone via the OMG issues page; you do not need to be an OMG member to raise an issue. But, the finalization process cannot consider enhancements, extensions, or perceived gaps in the specification, so please refrain from raising WIBNI issues as they will be closed without discussion. The OMG issues page also lists the open issues.
This OMG specification is distinct from the metamodel described in the Business Architecture Metamodel Guide V 2.0 (available in the Guild Resources->Whitepapers) though the two are closely related and a number of Guild members have worked on both the OMG specification and the Guild whitepaper. The OMG specification is intended to create a model interchange standard for tool vendors and was created in a process outside of the Guild collaboration team that produced the Guild metamodel whitepaper that included participants that are not Guild members. With a few exceptions (e.g. policy). the OMG specification includes everything in the Guild metamodel but may use different names and modeling configurations. The Guild metamodel collaboration team expects to produce an alignment document that will provide guidance on using the BIZBOK methodology with the BACM specification.
The BACM specification follows the OMG document conventions for specifications and the metamodel is defined in UML. Much of it is machine generated from a UML modeling tool. If you decide to inspect it, do not expect it to be an easy read. If you are contemplating implementing it, please let Jim Rhyne know as he is currently chairing the OMG finalization task force. You can send a personal message by way of the Thematix contact page.