Firefox Blocks Web-Based Cryptocurrency Miners
Third-party cookies are not the only one that one should worry about.
In the past years, web-based cryptocurrency miners have increasingly been abused by not just hackers but also websites and mobile apps to monetize by levying the CPU power of your PCs to secretly mine cryptocurrencies—often without your knowledge or consent.
In the wake of cryptocurrency mining scripts, both Apple and Google banned applications from listing in their app stores that mine cryptocurrencies on users' devices in the background.

Now, Firefox 69 also blocks web-based cryptocurrency miners by default, preventing draining your CPU usage and battery power on your computers.