Why there is another value of Xmx VM Options when i run embeded maven in intellj

I posted a question on https://stackoverflow.com/questions/62235174/why-there-another-value-of-xmx-vm-options-when-launch-embeded-maven-in-intellj  but didn't get a response

When i run maven goal from intellij, i see that it use a value of Xmx (1024) settings that i never set anywhere 

i updated the MAVEN_OPTS 
the maven settings in intellij : 

the maven goal config : 

the idea vm options : 

here is the workspace file : 

i also updated the surefire and failsafe plugins options but intellij always set Xmx to 1024M, and i don't know, from it gets this value