I doubt they think about Firefox much at all.
All of the metrics I've seen lately for a variety of web sites indicate that Firefox has less than 3% of the overall market.
The mobile situation is particularly bleak, where I've yet to see it even get close to breaking 1%.
At this point, Firefox's share of the market is closer to that of Mosaic, Navigator, and IE than it is to Chrome, Safari, and Edge.
I doubt they think about Firefox much at all.