ETOPS = Extended Range Twin Engine Ops Performance Standards
Extended Overwater means more fancy equipment (i.e. Rafts, vests, crew training)

For ETOPS, it has to do with being so far from a suitable alternate airport in the event an issue arises.
ETOPS time frames vary from 75 mins to 240+ mins.
I.e....over the Pacific you could be 270 mins away from a suitable alternate or over Siberia (land) you could be 210 mins away from a suitable alternate.

I believe the 787 is ETOPS 330

https://www.law.cornell.edu/cfr/text...-P_to_part_121

https://en.m.wikipedia.org/wiki/ETOPS