Copy field is just a directive that tells data should be copied from source
field A to target field B, so “copy field” itself is not a field (think “copy”
as a verb)
The target field and source field are regular fields and can take all kinds of
attributes like indexed=true or docValues=true
So
What do you mean with "
IMHO, the error message asks me to add indexed=true uninvertible=true or
docValues=true to title_s_lower, which is impossible, since it is a
copy-field.".
Copy-fields are like any other field, just the source for their values
comes from source fields.
You have full control
