You can clone with
HTTPS or Subversion.
Create / load a document
Hold down Ctl and click somewhere - the cursor is cloned
You can have loads of them and when you type anything the same characters appear at every cursor
How can this be disabled?
this is completely optional and added to editor with require("ace/multi_select").MultiSelect(editor);
you can either edit ace.js to remove that line or use your own implementation of edit function.
I plan to add init hooks, so that things like this can be configured with require("ace/config").setOption
but it will take some time