Man pages matching name devel::innerpackage in section 3pm:

Devel::InnerPackage.3pm.en	debian 10 / libmodule-pluggable-perl
Devel::InnerPackage.3pm.en	debian 11 / libmodule-pluggable-perl
Devel::InnerPackage.3pm.en	debian 12 / libmodule-pluggable-perl