Safari uses the same library as Apple's Reader. So it's a proprietary native blob.
Edit: While Chrome uses a native blob, I believe it's not proprietary. I think they use pdfium (https://pdfium.googlesource.com/pdfium/)
Safari uses the same library as Apple's Reader. So it's a proprietary native blob.
Edit: While Chrome uses a native blob, I believe it's not proprietary. I think they use pdfium (https://pdfium.googlesource.com/pdfium/)