Modify macro-privacy-mgr

I’m somewhat new to developing with FreePBX ( I’m used to working with other flavors of asterisk) and I need to modify macro-privacy-mgr. Whats the best way of doing that? Should I put my customized macro-privacy-mgr in extensions_override_freepbx.conf or can I keep it in extensions.conf? I’m hesitant to do that since I do not know what circumstances would need to arise to having it rewritten. Any insight at all would be greatly appreciated.