Core managed packages can have extension packages created for them that add functionality. We are considering that approach to support multiple languages so that the translation work can be on a delayed release cycle compared to the core package. Any one else doing this?
But the components for one language e.g.
translations/ja.translation-meta.xml are already bundled in the core package and that has been released. Eventually these components might be deletable, but progress on the platform delete component capability has been slow.
I assume that components already in the core package cannot also be added to an extension package? Or is there a "last install wins" convention?
(Trying to figure out if we are stuck with the one language having to stay bundled in the core package.)
A colleague suggested that perhaps a different namespace would allow duplicate files and perhaps it would. But in e.g.
ja.translation-meta.xml the label e.g.
<customLabels> <label>Eメールテンプレートが見つかりません。</label> <name>No_Email_Template_Found</name> </customLabels>
might be implicitly namespace qualified when inside a managed package. If it is the extension could not set a value for it and if it isn't we are back to having a duplicate name for something...
My next step here is to create some extension packages to discover what the constraints are. Results described in my answer.