PcdDebugPropertyMaskdeclared in MdePkg.dec file in $WORKSPACE\MdePkg is used to control DebugLib behavior. This PCD is FixedAtBuild type, meaning its value is determined at build time. The EDK II build system converts this pcd to the value configured in DEC or DSC to enable or disable the print ability.
IntelFrameworkModulePkg. One reason is that these packages are published as a base-supported package to facilitate module/platform development.