This provides a sidebar buffer which shows a "table of contents" for an associated outline-mode buffer. Basically, this shows you the sections of the outline-mode buffer, but not the bodies. This is to help you remember where you are in a large document. Simply use M-x outline-toc-mode to toggle activation of the outline-toc. Use 'M-x customize-group RET outline-toc RET' to adapt outline-toc to your needs. Much of this was originally adapated from David Engster's excellent minimap.el (https://github.com/dengste/minimap).