For implementing a reader/writer of ISOBus data you need the ISO 11783-10 specification. You need to buy this specification, and I remember clicking some TLDR agreement in the process. The bought specification-document is watermarked with my name.
Code implementing an ISObus reader/writer discloses many details about the ISO 11783-10 specification. I’ve once been told someone wasn’t allowed to publish their ISOBus code as Open Source, because of “infringement problems”. I don’t know the the exact reasoning. There is only little open source code on this subject, therefore I wrote this answer on stackoverflow: https://stackoverflow.com/a/48632418/193886
So my question is, can we legally publish code implementing ISO-11783?