Non-editable <line>, <polyline>, <polygon> elements (e.g. from LibreOffice Draw export)
The attached document is a DXF imported into LibreOffice Draw and then exported to SVG (since LibreOffice chooses a different elevation than Inkscape for 3D DXF). All extraneous guff has been removed to simplify the SVG content, leaving just the lines.
None of the lines are editable with the Node (F2) tool. They can be viewed, edited, re-coloured but the paths cannot be edited.
I tried creating a sample document in LibreOffice Draw (one rectangle and two paths) but that ended up with elements. DXF → LibreOffice → SVG uses and Inkscape can view those elements but not edit them. Possibly the SVG loader should convert to if there is no plan or possibility to handle elements.
Inkscape 1.2.1 (9c6d41e410, 2022-07-14)