hi,all 
      Contain one or more packages which also get installed for package builds, but a change in one of the packages does not trigger an automatic rebuild.

This is useful for packages that most likely do not influence the build result, for example make or coreutils.

The default package list for a build environment is: Preinstall + Required + Support + Packages from dependency expansion, use Support will install for all packages's build environment.

Some packages that most likely do not influence the build result, at the same time they only be depended by a small number of packages. Should not be put into the default build environment.

https://github.com/openSUSE/open-build-service/issues/13795