The permission "Check Out: View Loans" does not function as expected. I cannot find any jiras or record as to how this permission is expected to function, so I'm not sure I can provide guidance. I suspect that this permission is meant to be used when a FOLIO user has access to the Check Out app but does not have access to the Users app. In this case, when a patron is checking out an item and has active loans, the FOLIO user could click on the number of loans and go to the User Loans page and see the patron's loans without having access to the rest of the Users app.
As you can see from the attached capture (done today on Snapshot), it doesn't work that way. In this capture I'm logged in as a FOLIO User who has "Check Out: All Permissions" and "Check Out: View Loans" but does not have any permissions to the Users app.
In this case, for each patron that I look up, I can click on the loan link, and go to the loans page in Users, but it is a blank screen.
If the FOLIO user only has the permission set "Check Out: All Permissions" and does NOT have "Check Out: View Loans," they see the number of loans, but it is not a link.
ETA: Based on conversations with Prokopovych POs, it appears this permission was added in Honeysuckle, though we still cannot find the Jira that defined its development.
In Honeysuckle, when I am logged in as diku_admin, the links work as expected. When I am logged in as a FOLIO User on folio-honeysuckle who only has "Check Out: All Permissions," the link works as it does in Iris / Snapshot when you do have "Check Out: All Permissions" and "Check Out: View Loans." At least on Iris, if you just grant "Check Out: All Permissions" and don't grant "Check Out: View Loans", no broken link is presented.