I recently have been seeing similar messages from various stream providers that look like this. An intriguing message that tells you the stream provider has identified you are running the adblock extension and that you should unblock them to have full features. This is a fair enough response as most stream providers make their money from advertisments, but is trivially bypassed.
We can use inspect element to fully understand whats going on, one of the biggest identifiers is the word mask, which makes me want to investigate this further. Looking at the CSS elements, I can change various values.
The mask id has an attribute which if disabled, allows us to view normally. position:absolute. A very simple CSS trick to stop normal viewers from keeping adblock on. But developers for adblock could easily bypass such protection, there needs to be a server side aspect to this adblock protection to be effective in getting adblock viewers to see adverts. Client side protection is useless, because ofcourse, it’s client side.