For deployment to device or emulator options, MAF installs and launches the MAF application. If you deployed the MAF application in debug mode, a red icon appears on each screen of the MAF application, as shown in the upper-left portion of the figure. MAF applications that you deploy in release mode do not render this icon.
I Found it! https://docs.oracle.com/en/middleware/maf/2.5.1/develop/deploying-maf-applications.html#GUID-8806E3F2-5CDF-4FB0-9EC5-24C36E023A13
For deployment to device or emulator options, MAF installs and launches the MAF application. If you deployed the MAF application in debug mode, a red icon appears on each screen of the MAF application, as shown in the upper-left portion of the figure. MAF applications that you deploy in release mode do not render this icon.