It can navigate to items within the solution, including closed files.
The "ToggleBookmark" commands will either remove a bookmark if you're toggling from the line the bookmark is on, or remove the bookmark from it's line, and put it on the line you invoked the command on.
The "GotoBookmark" commands will navigate to the bookmark, opening the file if necessary.
The commands only exist as keyboard commands, and can be found in the keyboard configuration by searching for "SkoutSoft.Toggle..." or "SkoutSoft.Goto..." phrases.
