As a Wikipedia editor I want to have the possibility to move files from Wikipedia to Wikimedia Commons including the complete file history and the username so that it is clear to everybody what happened to the file.

See
https://de.wikipedia.org/wiki/Wikipedia:Umfragen/Technische_W%C3%BCnsche/Top_20#Technisch_sauberes_Verschieben_von_Dateien_nach_Commons_unter_Beibehaltung_der_Versionsgeschichte_und_des_Benutzernamens (in German).

Further details:
Precondition: global account (SUL)
Use import/export feature
Concerns two (three) histories: file description history, file history, binary file itself (all versions)
Perhaps possible as part of or based on the GWToolset.

Effort:

Needs to be further discussed with:

This is part of the Top 20 wishes of the German community