While browsing this site - https://bratislava-slovakia.eu/travel/vienna-bratislava/boat - I found that it was using 100% of my CPU. That was 800% of a core on my laptop, and almost 4800% of a core on my workstation. It's mining bitcoins. So, the first request would be mitigations so that this doesn't happen, at least throttling the tab when it isn't visible. It's doing all of this mining on service workers.

However the clearer bug is that on my laptop when I went to profile the page to figure out what was going on (I suspected mining but didn't know for sure) the tab crashes. That is, I opened developer tools and started profiling and then at some point the tab crashed.

I've attached the crash dump. The page is still mining bitcoins, FWIW, but I can't reproduce the crash anymore.

Some twitter discussion of the issue can be found here:
https://twitter.com/BruceDawson0xB/status/1000125230239674369

 

Deleted: 7834cfe8-02f1-47f7-990e-8a5a98921d6b.dmp 1.6 MB

7834cfe8-02f1-47f7-990e-8a5a98921d6b.dmp 1.6 MB Download