Carnegie, The Bill and Melinda Gates Foundation, and the National Council of Nonprofits guidance all have policies/guidance on conflict of interest that are publicly available (as highlighted in this comment).
Does Open Philanthropy also have a public document on its conflict of interest policy?
Given the prevalence of polyamory in the community (including amongst grantmakers) and the reported insularity / cliquey-ness of the Bay Area EA communities, I believe it makes sense for Open Philanthropy to make its internal policy on this public (and therefore open for critique).
I believe it also makes sense to show when policy may have been violated (especially in light of a rumour about a Senior Program Officer at OP and a grantee in a metamour-relationship being 'verified'.) I would find it hard to believe if the policy has never been violated across the 100s or 1000s of grants OP has made.
Back in March 2017, in a writeup about the $30M grant recommendation to OpenAI, OpenPhil were transparent about HK (then-CEO of OpenPhil) being engaged to DA's sister, while DA was a researcher at OpenAI and also a technical advisor to OpenPhil and living in the same house as HK. (This was before the two siblings were appointed to VP positions at OpenAI, which I'm not aware was ever publicly reported by OpenPhil).
As you mentioned in your comment, OpenPhil changed their policy about publicly disclosing relationships. If today OpenPhil faces CoI situations that are similar to the ones they faced when recommending that $30M grant to OpenAI, they may not mention those CoIs publicly at all. It is also possible that the relationship disclosures about the $30M grant are publicly available on OpenPhil's website today only because they were publicly discussed prior to the change in OpenPhil's policy (I don't know whether they were). Quoting from OpenPhil's Relationship Disclosure Policy: