It would great to bring in Skim reading compatibility with Geospatial PDF.
https://gdal.org/drivers/raster/pdf.html
https://north-road.com/2019/09/03/qgis-3-10-loves-geopdf/
https://spatialthoughts.com/2015/10/25/geopdf-gdal/
http://latuviitta.org/documents/Geospatial_PDF_maps_from_OSM_with_GDAL.pdf
The PDF parsing and display is done by Apple's PDFKit, we only use it in Skim. So if ou want extended capability of viewing PDFs, you should petition Apple, not us.