@Rüdiger: That is intentional and is set in /etc/apt/apt.conf.d/01autoremove which belongs to apt.
[...] Never-MarkAuto-Sections { "metapackages"; "restricted/metapackages"; "universe/metapackages"; "multiverse/metapackages"; "oldlibs"; "restricted/oldlibs"; "universe/oldlibs"; "multiverse/oldlibs";
};
@Rüdiger: That is intentional and is set in /etc/apt/ apt.conf. d/01autoremove which belongs to apt.
[...] MarkAuto- Sections
"metapackages" ;
"restricted/ metapackages" ;
"universe/ metapackages" ;
"multiverse/ metapackages" ;
"restricted/ oldlibs" ;
"universe/ oldlibs" ;
"multiverse/ oldlibs" ;
Never-
{
"oldlibs";
};