PDF Copying Assistant for Musescore 3.0: How's It Going?

According to a page made more than 3 years ago, discussing the changes to be made for Musescore 3.0,

"PDF Copying Assistant: In addition to the experimental online PDF-to-MSCZ converter, MuseScore 3 will be able to recognize the basic structure in a PDF (systems, barlines, line breaks), provide a blank score matching those specifications, and synchronize it visually with the PDF, making it easy to transcribe what you see on the right into the empty measure on the left. Work on this actually began some years ago, but was cancelled before MuseScore 2.0—now new contributor Liang Chen has rebooted the effort."

How's that going? Has it been implemented or completed yet? If so, how do you use it? I'm genuinely interested.