You can automatically apply the best emulator and core for arcade systems (Neogeo / Mame / FBA / FBNEO). ARRM searches the database from 'BestArcade'.

Here's the procedure to follow :

Select the system (only one) then click on Display

When the Database is filled with the Roma found,

Select the games for which you want to change the emulator and the core (highlight them) then click on the ' Update Core ' button.

This operation adds or updates, in the gamelist.xml, the tags <core> and <emulator> . These tags will be written during the next backup of the gamelist via the button ' Create gamelist.xml for roms '

The emulators and core can evolve according to the versions of Recalbox and Batocera software. You can update the list of emulators and core, by clicking on the button ' Edit Arcade core ' which will open the file '%appdata%\Nexouille soft\arrm\database\batocera_arcade_core.txt' for Batocera or '%appdata%\Nexouille soft\arrm\database\recalbox_arcade_core.txt' for Recalbox.

The file looks like this:

## for batocera system. Choose which emulator and core for arcade system
## first parameter : don't change , Second parameter : emulator , third parameter : core
## Don't add lines to this textfile, you can just modify emulator and core only
## ARRM lookup in a database based on 'BestArcade4Recalbox-18-03-30' , he searches game with Status 3, then Status 2 and finally status 1 and set the appropriate emulator and core. 
## BestArcade4Recalbox list : https://docs.google.com/spreadsheets/d/1F5tBguhRxpj1AQcnDWF6AVSx4av_Gm3cDQedQB7IECk/edit?usp=sharing
## FBNEO rom set : 0.2.97.44
## MAME2003 romset : 0.78 
## MAME2010 romset : 0.139
reference_file;BestArcade4Recalbox-03-06-20
mame2003romset;0.78
mame2010romset;0.139
fbneoromset;0.2.97.44
## YOU CAN JUST CHANGE THE SECOND AND THIRD PARAMETER IN EACH LINE BELOW  (xxxx;emulator;core) if multiple core are available for a given status it takes the first line below, otherwise fallback to the second then the third
fbneo;libretro;fbneo
mame2010;libretro;mame0139
mame2003;libretro;mame078plus
mame2003plus;libretro;mame078plus

Depending on the evolution of the emulators / core you can modify the 2 nd and 3 rd parameters of the last 4 lines which correspond to the emulator (2nd parameter) and to the core (3rd parameter). The 1st parameter must not be modified:

fbneo;libretro;fbneo
mame2010;libretro;mame0139
mame2003;libretro;mame078plus
mame2003plus;libretro;mame078plus