Goto - Settings → System → CoreELEC
If you can see this screen with the choices below then it was installed.
Assuming you have a DV TV, these settings are also the best choices if you want to play DV with FEL and every other format in its original format. If you want to convert any other format to DV then change the setting from “off” to “Dolby Vision” with the exception of “HLG HDR” (given an AMLogic bug) and of course “Dolby Vision”. This will convert those formats to DV using the VS10 Engine.