To test this issue, I translated the lead section of the Wikimania article from English to Greek. At first, in the new article page, that I've been redirected to after successful publishing in Section Translation, the article didn't seem to be linked to the English Wikimania article. However, 1-2 minutes later the article appeared properly linked through Wikidata. By looking at the history of the "Wikimania" page in Wikidata, I checked that this link was created during the publishing, although it took few minutes. I'm also attaching a screenshot of this evidence. @EChukwukere-WMF could you test this task again based on my input? Maybe you'll have to wait a few minutes until the link has been created in Wikidata.

@Pginer-WMF You are right. I misread the description. Sadly, this is not a bug, it's a missing feature. Since the publishing happens in the target wiki of the translation, we need to redirect the user to the Content/Section Translation application inside the target wiki. However, since there is no target language, it is unclear where the user should be redirected. In this sense, selecting a wiki to redirect to, is basically equivalent to select a target language. Do you have any suggestions how we should handle this case? FYI this doesn't seem like a quick fix to me, this is why I'm having some second thoughts if we should invest effort in this, or we should just fallback to a simple solution like selecting the first suggested language as target language.

This is not the case anymore. The template can be properly adapted. @Pginer-WMF I think we can consider this ticket done.

@Pginer-WMF This issue can no longer be reproduced and probably can be closed. Screenshot from test wiki:

As demonstrated in the following screencast (from Spanish wiki) this issue doesn't seem to be relevant any more. The issue was also tested on test wiki with the same results.

The functionality seems to work properly on production wikis, as demonstrated in the screencast below - from Greek (el) wikipedia:

These issues seem to have been fixed already. More specifically, about Content Translation (desktop), the page is pre-selected properly as demonstrated in the following screencast:

In order to properly support this feature, we need to define what qualifies as "translation" in this context. More specifically:

1. Do draft translations qualify for these stats?
2. Do section translations qualify as translations? Please note that per design it's impossible to identify as "published" a section translation that has been published, then edited again (without being published again). Such a translation will be considered as "draft".
3. Regarding the monthly stats, do we consider a translation to be done in a specific month based on its starting date or based on its latest update?

Screencast after fix:

Screencast from my local installation before fix:

Adding to Pau's comment above, I checked that the module that registers the “Edit language links” action button is the wikibase.client.vector-2022 module. I checked the loaded modules for the above page (using mw.inspect() inside the Developer’s console) and the module doesn’t seem loaded. This is why the button is not visible. I checked the conditions used to add the module, in the codebase and I believe it's the following condition that prevents the module from being added:

As it's apparent in the screenshot below, the hash for the section title is being added, even when not needed, i.e. when undefined.

Seems duplicate of this task: T328143

@Pginer-WMF based on my input above, I would suggest that this task can be closed.

Additionally, regarding case (a):

For case (b) I tested the "mffrequentlanguages" entrypoint (this is the 'campaign' URL parameter for this entrypoint) in production wikis and the event seems to be properly logged with "frequent_languages" event source.

The process to register a new action item inside the actions menu of the ULS is quite simple. All you need to do is to create an action item object and then register it inside the actions menu item registry like that:

mw.uls.ActionsMenuItemsRegistry.register( actionItem );

ULS will take care of everything else. The action item object is expected to have the following properties: name (any name of your preference), icon (the title of the desired icon as defined inside OOUI icons), text (the label of the action item), href (the href of the action item if it's an anchor) and handler (a method to be executed on action item click). If the href property is present, the handler is being ignored, otherwise if href is missing, handler should be defined (otherwise the action item would be useless).