Revit is still exporting a PCP plot style file when exporting DWG files.
So, still needing a way to convert a .pcp file to .ctb file.
Try renaming the *.PCP file to *.CTB;
After renaming *.PCP to *.CTB it opened in the Plot Style Table Editor.
It looks like you're new here. If you want to get involved, click one of these buttons!