Bookmarks are a collection of metadata items you are interested in, referring to frequently, or working on, gathered in one place. When viewing a metadata item, you wish to bookmark, simply click on Add item under the Bookmarks menu on the right. You can also add items to your bookmarks from the search results listing, by clicking on the three lines icon on the right of the metadata item title and clicking on Add to my Bookmarks.
In legacy METeOR this feature was called My Items.
On multi-selection pages such as Workgroup landing pages, a Registrar can also use Bookmarks to bulk endorse metadata within their Registration Authority.