Hi, in the 'Other APIs and protocols' section, this string (https://translate.koha-community.org/translate/koha-manual/apis_protocols/fr/?checksum=c1c7527373524acf) tells us that <xact_date> has been described above but I don't see anything above which explains this field.
I'd be surprised if it was really called <xact_date> - and not <exact_date> - too! So maybe even more to review in this section.