I'll do this in two steps. First the translations, then the fallback (although I don't think I remember having changed myself a language fallback in the past so I am not aware of the consequences and if things would break, so I'll play safe here).

Change 613110 had a related patch set uploaded (by MarcoAurelio; owner: MarcoAurelio):
[mediawiki/core@master] MessagesVec.php: update translations

https://gerrit.wikimedia.org/r/613110

Change 613111 had a related patch set uploaded (by MarcoAurelio; owner: MarcoAurelio):
[mediawiki/core@master] MessagesVec.php: remove Italian as fallback language

https://gerrit.wikimedia.org/r/613111

@Sakretsu Is the use of the word File for NS_FILE intended? English names always work so it'd be redundant to add it.

Removing Wikimedia-Site-requests: this is a change that affects MW core, not just vecwiki.

@MarcoAurelio yes, it is. I'm not sure about the redundancy though. I took MessagesIt.php as an example. By the way, thanks for the help.

Fallback languages are not decided by Wikipedia consensus. The Italian fallback for vec must stay.

A Venetian sysop explained me the reason here when they asked me to open this task. Basically, Venetian users believe English is easier to understand for those who live in Brazil and speak Venetian. The most active Venetian project affected by these changes is by far vec.wiki where the community comes together. I don't think we need anything else. If this is a mistake, they can still decide to revert it.

Change 613110 merged by jenkins-bot:
[mediawiki/core@master] MessagesVec.php: update $namespaceNames and $namespaceAliases

https://gerrit.wikimedia.org/r/613110

Change 613111 abandoned by MarcoAurelio:
[mediawiki/core@master] MessagesVec.php: remove Italian as fallback language

Reason:
Not a pacific change, per Task.

https://gerrit.wikimedia.org/r/613111

@Nemo_bis According to what reasoning should fallback remain in Italian? What is the absurd logic? We Venetophones from Veneto and Brazil would like to know what logic the fallback should remain Italian and why not English as the Catalan project. Thank you.

In T255938#6344207, @Nemo_bis wrote:

Fallback languages are not decided by Wikipedia consensus. The Italian fallback for vec must stay.

Do we know who decides that and where it is recorded?

In T255938#6534145, @Fierodelveneto wrote:

@Nemo_bis According to what reasoning should fallback remain in Italian?

Please read their comment.

What is the absurd logic?

It's not absurd, we're hopefully following an agreed upon standard.

We Germanophones from Veneto and Brazil would like to know what logic the fallback should remain Italian and why not English as the Catalan project. Thank you.

Hopefully we can find that out upstream for you.

@RhinosF1 Hello, thank you very much for the answers. I said that the logic is absurd, precisely because none of those who prevented the application of a democratic and logical choice, explained why Veneto would be linked to Italian, and conversely, why Catalan and Basque are not related to Spanish. I understand that Veneto is spoken as a minority language in Brazil, where Italian is not covered, in Croatia (where Croatian is spoken), Slovenia (where Slovenian is spoken) and Italy (where Italian is spoken). We in the projects the Venetian language raise with great firmness the question of the change of fallback in English, out of respect for all Venetians and because the data of Wikidata, if not translated, would arrive in a language unknown to a large piece of the Venetians and that nothing has to do with the language of vec.wiki. Thank you.

While I fully understand your wish, If as @Nemo_bis, claims we follow an externally set standard then it might be the case that our hands are tied and we need to review how whoever made the call came to that decision and have it reviewed but that could be a long while or come up with an answer for you.

@RhinosF1 Hi, thank you for your understanding! I exclude that this can be a default standard, otherwise Catalan and Basque should also depend on Spanish, unless there is an irregularity in this. In any case, we give the maximum availability to solve this problem, not only for vec.wiki, but for the good of all linguistic projects that in the future find themselves in this situation. Thanks again!