The Library Publishing Coalition has released An Ethical Framework for Library Publishing Version 1.0..
Here's an excerpt:
Library publishing is distinguished in part from other types of scholarly publishing by a focus on adherence to the values and ethics of librarianship. An Ethical Framework for Library Publishing supports good practice in this area by providing resources and guidance in a number of ethical areas of importance to library publishers. Version 1.0 (published July 2018) covers publishing practice; accessibility; diversity, equity, and inclusion; privacy and analytics; and academic and intellectual freedom.