How to restrict JavaScript from enumerating ghost plugins?

When I go to BrowserLeaks and test Firefox it shows the following plugins installed on my system.

plugins PDF Viewer, internal-pdf-viewer, Portable Document Format
Chrome PDF Viewer, internal-pdf-viewer, Portable Document Format
Chromium PDF Viewer, internal-pdf-viewer, Portable Document Format
Microsoft Edge PDF Viewer, internal-pdf-viewer, Portable Document Format
WebKit built-in PDF, internal-pdf-viewer, Portable Document Format

I am on Firefox and I do not have any of the above mentioned plugins in Firefox. In Firefox I only have a single plugin installed, OpenH264 Video Codec provided by Cisco Systems, Inc.

When I go to EFF CoveryourTracks website it shows me these plugin and says:

One in x browsers have this value: 1.57

How can I stop or modify the enumeration of plugins by JavaScript? I would like to only have, “Chromium PDF Viewer, internal-pdf-viewer, Portable Document Format” reported by JavaScript.