The file
Trial.dxf is a regular DXF file, so it is not related to the cited GitHub issue.
The file is not empty, but is has no entities. It contains the layer list and 3 blocks, that explains the file size.
There is not chance to see in the dxf file if there were any entities at any time.
Maybe they were deleted by accident?
You can take a look to the storage location, maybe you find one of the files #Trial.dxf or Trial.dxf~.
These are auto save files and possibly show an older instance of the drawing with entities.
You can rename them and then open with LibreCAD.
Armin
investing less than half an hour into Search function can save hours or days of waiting for a solution