Hi @Florent_F, yes app is a legacy of an earlier incarnation of Grist, as a desktop application. It plays no role anymore. I see it is used in grist-electron:
But if you read the mergedServerMain code, everything it enables is already enabled by home. For the original desktop application (which no longer exists), it was possible to run the app without having a “home” db. grist-electron just goes with the flow and uses a home db, so there is less divergent code to maintain.