This is a little one, but a time saver all the same. I can never seem to find the “right” navigational route to the page which shows the permission levels (I think of them as roles and the page name backs me up!) in SharePoint. It’s the page at /_layouts/role.aspx. So:
From this page, you can check the underlying permissions for each permission role as well as create new roles.
Happy Groundhog Day!