In the same vein as this:
In IATI, organisations are allowed to exclude activities (either entirely, or just certain pieces of information) from publication as long as they state (in general terms) the grounds on which activities will be excluded. Organisations briefly state their exclusions policy in the IATI implementation schedule (though not in the common standard implementation schedule). However, others provide a link to a specific policy on their website which explains in detail the grounds on which exclusions will be made. This may include rationale, explanations of process, etc. or it may be a simpler document.
(NB: this proposal does not seek to deal with the issue of activity-specific exclusions in more detail, which would require a more thorough proposal and would probably be an integer change in some respects.)
An exclusions policy cannot be published in IATI data even though it would comfortably work as an organisation level document-link and would not be substantially new content, as it's already covered in other ways under the standard, albeit in a less useful format.
Add a new document-link category code: for exclusions policy, at the organisation level. This could be described as "An exclusions policy for the organisation that explains the grounds on which activities will be excluded from publication."