Firefox android hardcoded DNS?

Privacy Questions
1

Hi,

I blocked the Google DNS servers (8.8.8.8 and 8.8.4.4) on my mobile, and that immediately blocked firefox (android) from working.
TOR still works, so the internet connection is working.

Does this mean that the Google DNS servers are hardcoded into Firefox android?

2

I don’t use Firefox Android. But is there an option for Custom DNS like in the deskotp version ?