The old spec has a short introduction to "Range modification under document mutation" here:
I kind of like that since it gives the reader an idea of how mutations affects
ranges "in a nutshell". I can't find anything like it in the new spec.
Specifically, I'd like the new spec to adopt the general principles:
"There are two general principles which apply to Ranges under document mutation: The first is that all Ranges in a document will remain valid after any mutation operation and the second is that, as much as possible, all Ranges will select the same portion of the document after any mutation operation."
Yeah, we need a section 'Introduction to "Ranges"'. It can probably be one or two paragraphs there with pointers to the various algorithms throughout the specification.