Open With Adobe PDF Reader 2.0.0 has been blocked for your protection.

Why was it blocked?
Version 2.0.0 shipped with a hidden coin miner, which degrades performance in users who have it enabled. Version 1.2.3 currently available on AMO is not affected.
Who is affected?
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.