In T137584#7591141, @Xover wrote:

@Agabi10 Did you give up on this patch? It looks really useful to me, and from the review comments it didn't look like there were any insurmountable problems (just maybe some documentable limitations due to the architecture context).

Sorry for the late response: what I (as a user) was expecting from -ns:6 was to filter source pages by ns, then fix them.
However I never thought that source and destination ns may be different (because I expect a redirect from the file namespace to point to an actual file, so again to the file ns), but in the end I would expect it to filter the source.

python pwb.py category add -cat:"Zone Sole e Luna"

then when prompted I wrote the new category (Zone Ultrasole e Ultraluna). The bot showed the differences, I answerd y (to accept changes). Then the bot went on saying

Current categories:
* Categoria:Isole
* Categoria:Zone Sole e Luna
* Categoria:Zone Alola
* Categoria:Zone Ultrasole e Ultraluna
Akala is already in Categoria:Zone Ultrasole e Ultraluna.

multiple times (Akala is the first page in the category Zone Sole e Luna), and in the end

86 pages read
1 page written
Execution time: x seconds
Read operation time: y seconds
Script terminated successfully.