From http://leoeditor.com/tutorial-pim.html, it looks like a 'clone' means that the node is presented in several places in the document, but each of those several places bring you back to one, single node.
It seems like org-mode ought to be able to do this, too.
At least, it's weird that emacs/vim _can't_ do something. I can't remember the last time anyone said that about, well, anything :)
A clone is not a copy. When you clone a node in leo, the same node can appear in multiple places at once. If you edit any of the clones, the original is updated.
One use case: You're trying to fix a big in code. You can create a new node and place under it clones of all relevant code (which may exist across multiple files) for the bug. And not just code but also collateral for tests (e.g. unit test or input files that reproduce the bug etc). Oh and might as well clone the bug report as well.
So all that you need to work with the bug conveniently under one node. Just edit there and all relevant files get updated.
Leo is powerful and has a decent user base. It is the closest thing I've found to Emacs in the Python world. Unfortunately the documentation is really bad and I just don't have time to learn it without good documentation. I toyes with the idea of becoming a master at it just so I can write proper docs but life is too short.
https://www.gnu.org/software/emacs/manual/html_node/org/Stru...