The page on Time Filters mentions in the intro:
Datomic databases can be filtered with the time-based predicates
asOfandsince. Or, you can bring your own predicate withfilter. In addition, you can get an unfiltered view of all history viahistory.
However the Client API does not have the filter function, and I presume Cloud does not support that?
It looks like this page might have been copied from On-Prem documentation and the section about filter further down removed, but the highlighted sentence was left in.
I think it would be clearer if it is also removed (it threw me off course for a while, thinking predicate filters are supported). The paragraph will then read like this:
Datomic databases can be filtered with the time-based predicates
asOfandsince. In addition, you can get an unfiltered view of all history viahistory.