I guess Vinh Tran is talking about the Nexus EN15804 add-on for ecoinvent 3.10, since the methods are only inside this database.
EN 15804+A2 (EF 3.1) ... Method to calculate all EPD indicators, including the environmental indicators with the impact categories from the EN15804 method from the JRC (based on EF 3.1) and including all inventory indicators (like waste, output flows, primary energy indicators etc.).
Environmental EN 15804+A2 (EF 3.1) ... Method to calculate only the environmental indicators with the impact categories from the EN15804 method from the JRC (based on EF 3.1).
The environmental indicators are the same in both methods, just that the first one also calculates all the inventory indicators. So the second one "Environmental EN 15804+A2 (EF 3.1)" is not necessarily needed, but maybe useful for some users?