Plugin backend does not work with Grafana 13.0

[arvidsnet]

Save & test fails, in dev tools we can see that
PUT /api/datasources/uid/dfopvxcdpts00a succeeds
but
GET /api/datasources/10/resources/reports fails with 404
and in Grafana logs we see

logger=context userId=1 orgId=1 uname=admin t=2026-06-10T16:33:38.786512491+03:00 level=info msg="Request Completed" method=GET path=/api/datasources/10/resources/reports status=404 remote_addr=127.0.0.1 time_ms=2 duration=2.259189ms size=29 referer=http://localhost:3000/connections/datasources/edit/dfopvxcdpts00a handler=notfound status_source=server

I suppose handler=notfound means that this request is not routed to plugin backend.

Regards, Arvids