What URL do I use to view an OG membership entity?
I don't think that there is a page you can view the membership. I've just skimmed the code of OG module and didn't found any relating part which displays a membership in a separate page.

However, since memberships are entities, it should be possible that you can setup a view which takes a membership id as contextual filter and display it in a selected view mode.

Here is how you do that with views:


Create a new view visiting admin/structure/views/add


Give your view a name like View Membership
Set it to Show OG Membership
Set a Path with a placeholder like view-membership/%
Display format Unformatted list of Rendered entity
Items to display 1, uncheck Use a pager
Continue &amp; Edit

Under Advanced section, add a contextual filter OG membership: Og membership ID


WHEN THE FILTER VALUE IS NOT IN THE URL: Show "Page not found"

Save
Visit the page view-membership/&lt;membership_id&gt; and you'll see the membership entity.