Sometimes (i.e. : https://musicbrainz.org/release/4c92b5fc-d292-4b5a-a75a-13d48f5c6aca), the "vocals" tag is missing in the French version of the site.
The content is there (in the database) !
But the link with a tag label is missing.

Consequence : when using Picard (or any external tool), the matching is not properly done and the "vocal" tag attribute values are not taken into account...
(that's a very important information when "Various Artists" are producing on stage...)

Illustration:

EN version:
===========
3 Satisfaction
vocals:
Jean-Louis Aubert, Lââm, Yannick Noah, Natasha St‐Pier and Ophélie Winter
recorded at:
AccorHotels Arena in Paris, Île-de-France, France (2005-01-21 - 2005-01-24)
live cover recording of:
(I Can't Get No) Satisfaction (2005)
writer:
Mick Jagger and Keith Richards (Rolling Stones guitarist)
(...)

FR version:
===========
3 Satisfaction
:
Jean-Louis Aubert, Lââm, Yannick Noah, Natasha St‐Pier et Ophélie Winter
enregistré à :
AccorHotels Arena dans Paris, Île-de-France, France (2005-01-21 - 2005-01-24)
en public enregistrement une reprise de :
(I Can't Get No) Satisfaction (2005)
auteur :
Mick Jagger et Keith Richards (Rolling Stones guitarist)
(...)