The WotC article Unearthed Arcana: Modifying Classes creates the "Favored Soul" sorcerous origin, which grants the the sorcerer the Extra Attack feature at level 6.
Say I made Favored Soul sorcerer go up to level 6, and then multiclassed into Ranger to get its Extra Attack at level 5. Would the two Extra Attack features stack so that I could get 3 or 4 attacks in a turn?
Best Answer
The Extra Attack feature from different sources does not stack.
The rules for stacking Extra Attack as they relate to non-fighters and fighters are in the Multiclassing section of the Player's Handbook, pg. 164:
The only class that can expand the ability of Extra Attack to make more than 2 attacks per Attack action is the Fighter. The Fighter's Extra Attack feature says (PHB, pg. 72):