Download the NexGenEFI Digital Dash Community Edition.
You will need to UNZIP the files.
Current version which you can see in the CONFIG screen is v0.09i as of 03/21/2023.
This is the compiled firmware for the Community Edition which runs on the Arduino MEGA: NexGenEFI Digital Dash Community Edition Download
Download the Nextion Display layout
7″ Nextion Intelligent Series. Download 7″ Display layout
Layouts included below. Last image is the CONFIGuration screen.