This corresponds to HPS 6f festivus and LH2019 VI***, but is a copy of GFS 6f (with correction of typos) which is very different from those two (Si bémol and a different closing formula). D. Crochu lists it as the "main" festive Venite tone 6, probably due to its antiquity, but the version listed as VI** in LH is used by communities so I insist on listing it as the default 6f.
Note : rsigns are taken from the equivalent score in LH83 even though it is quite different melodically