Although I had my dealer change out my brake fluid, so I don't know what spec they used, the covers on my Empulse R, purchased 12/12 say to use DOT 3รท5 , whatever the heck that means.
In researching this cryptic term, I found this on a Ducati forum:
"That lid confuses almost everybody, it means
use DOT 3 and anything up to but not including DOT 5 which is a silicone
fluid which is NOT compatible with 3 and 4 which are compatible.
DOT 4 has a higher boiling point so use DOT 4 if available."
Oddly, I also learned that DOT 5.1 is NOT silicone-based but is glycol-based like 3 and 4. Reminds me of the saying, The nice thing about computer standards is that there so very many to choose from. And also, recently, since DOT is a government entity: NSA, the only government agency that listens.
(I'd go with Brian's direction on this to use DOT 4!)