Vlad It will swap between the "Add", "Bookmarks", and the input field.
This is with this option in system preferences off.
Although the behavior in Safari is the same with this preference off as well.
It is not always a good idea to copy Safari exactly, and the folder that the bookmark is should be considered a "control", as well as the input field. So for example, if we were speaking about this input field, with the box not ticked in the image shown above, it should swap between the "Bookmarks" and input field of the bookmarks in Orion, because in Safari with that same setting off it only swaps between the "Bookmarks" and "Description" fields and ignores the "Cancel" and "Add" buttons completely in the tab cycle.
In the above image, the first behavior is with the option shown in the first image ticked on. The subsequent behavior of simply focusing the input field when pressing the tab key should instead swap between the folders and the input field, as Apple has not really changed this specific behavior in years nor has any guideline on what is considered a "control".