When I have a problem in a Writer document, it would be nice to have a clean way to reduce a large document to something smaller that just shows the problem, for debugging and so I can attach a small example to questions like these.
You can select large regions by dragging (eventually), then delete.
We have Select All. New Select from Start and Select to End option might do my job. Deleting onwards ought to be easy, but deleting backwards might have nasty side-effects. Perhaps a more general tool might be to add Select From… and Select To… options.
I found an earlier suggestion for saving pages A-B as a separate document. This is a different way of doing the same thing. If you could save the current page as a separate document to report some problem, you would still have to re-load the document and check the problem still happened. There were also objections because the page breaks were not part of the document.