No known consumers from the MW ecosystem according to codesearch: https://codesearch.wmcloud.org/search/?q=languagepairs&files=&excludeFiles=&repos=
Next steps
@abi_ are you aware of any access log that would allow us to see if this entry point is still being called?
https://grafana.wikimedia.org/d/F7rttgqmz/cxserver?orgId=1&from=now-30d&to=now&timezone=utc&var-dc=000000018&refresh=30s&viewPanel=panel-12 maybe. There seems to be a drop-off in codfw around two weeks ago, but same does not show in eqiad. Some of the traffic is probably just automatic spec-driven testing.
Outdated CX setups like test instances or even development environments may also be calling this endpoint.