I do apologize if similar question already put, but I haven't found one.
I would like to change the default project description file name (called README.md) to be a custom name (let's say XXX.md) and I wonder if it is possible to be the XXX.md the initial readme file for the project (typical situation: you open the project Code page and you will see the content of XXX.md down at bottom).
I would like to verify if this approach possible in general, but I am mainly interested in Github and Bitbucket services. I briefly checked project settings and I cannot find there such customization. Is it even possible?