To clarify things: by replace, do you mean that "filemover" group should be removed in favor of this new "mover" group? And who should be able to add users to this group, sysops or bureaucrats?

Thank you Glaisher, summer brought me a strong flu and I tend to miss too many things.
This group should be assigned by sysops and removed by 'crats.
Dealing with replacing yep, I mean filemover group shouldn't longer exist, poke me if I'll have to move current members to the new group.

Change 218926 had a related patch set uploaded (by Glaisher):
Create 'mover' usergroup at Italian Wikipedia

https://gerrit.wikimedia.org/r/218926

Change 218928 had a related patch set uploaded (by Glaisher):
Add i18n messages for 'mover' user group

https://gerrit.wikimedia.org/r/218928

Change 218928 merged by jenkins-bot:
Add i18n messages for 'mover' user group

https://gerrit.wikimedia.org/r/218928

• https://gerrit.wikimedia.org/r/218928 (branch master): WMF-deploy-2015-06-16_(1.26wmf10)

Change 218926 merged by jenkins-bot:
Create 'mover' usergroup at Italian Wikipedia

https://gerrit.wikimedia.org/r/218926

@Krenair wrote on gerrit change:
I'd kind of prefer to have it properly logged etc.... At least we should make sure their page about the filemover group explains the change to this group so people can follow it.

Please do update the local page(s) as necessary.

(In the end @Vituzzu, a local bureaucrat, removed the rights, I sync'd the change, and they added the new rights in place. So it's fine, we didn't rely on migrateUserGroups)