Addon Packages (langpacks)
Langpacks is a concept of dividing translations into subpackages in the case the size of translation is enormous and/or the package is part of core image that should be minimal.
Packages that exist solely to contain additional language translations must be named in the syntax <pkgname>-<langcode>, where <pkgname> is name of the package the langpacks belong to and <langcode> is a valid language code from /usr/share/xml/iso-codes/iso_639_3.xml or from /usr/share/i18n/locales/. Specifically, the langcode value used in the package name must match the langcode identifier used in the directory path by upstream for the language translation files.
Langpack ecosystem does not need any procedural logic in form of plugin - it rather takes advantage of RPM weak and rich dependency features. Langpack dependencies are computed by package manager (DNF or PackageKit) so it's crucial to define following relation into langpack definition in the spec file:
Supplements: (<pkgname> = %{version}-%{release} and langpacks-<langcode>)
Example:
Suppose you have a package with following spec file:
Name: php-horde-Horde-Perms ... %files -f Horde_Perms.lang /usr/share/pear-data/Horde_Perms/locale/ ...
In order to create langpacks for each language (/usr/share/pear-data/Horde_Perms/locale/<language>/LC_MESSAGES/Horde_Perms.mo translations), you would need to add change for such language in the spec file. The snippet below shows the definition of one langpack for bs language by altering the spec file defined above.
Name: php-horde-Horde-Perms ... %package bs Supplements: (%{name} = %{version}-%{release} and langpacks-bs) %files bs /usr/share/pear-data/Horde_Perms/locale/bs/LC_MESSAGES/Horde_Perms.mo
%files ...