We brewed our Jalapeno IPA again this year. Must have got some hot peppers, Because it’s much spicier than in years past.
Anyway, we put in 2 pounds of fresh, sliced, frozen peppers in the boil with about 10 minutes to go.
My OG was 1.064, FG was 1.010. So it’s about 7.2% ABV
But I got to thinking about the peppers. Would they have any effect on those numbers? 20 gallon batch.
to the extent fermentable sugars were extracted they would have an effect. I suspect it’s pretty small though.
looks like Jalepenos have ~ 4 grams of sugar per 100 grams of peppers. so your 2 lb ~40 grams of sugar or ~.1 lbs. not much in a 30 gallon batch.
What Mort said… 
Not sure what the brix is on peppers, but my guess is at most it would lower your OG by a point. Probably even less than that. Regardless, its effect would be too small to he concerned about, IMO.
I think this is true of any vegetable or fruit - even sweet fruit like berries. They add sugar and also volume (from water in the fruit) and so the affect is often small and usually a slight reduction in gravity, never an increase.