ByTypeDispatchingEntityPrefetcher should be moved to DataModel Services, where the interface is defined.
There are no dependencies on Wikibase itself in the implementation that would prevent from moving it.
Other ByTypeDispatching services defined in Wikibase at this point (ByTypeDispatchingEntityIdLookup, ByTypeDispatchingEntityRevisionLookup and ByTypeDispatchingPrefetchingTermLookup) should not be moved as they bind against other parts of Wikibase.
This task has been assigned to the same task owner for more than two years. Resetting task assignee due to inactivity, to decrease task cookie-licking and to get a slightly more realistic overview of plans. Please feel free to assign this task to yourself again if you still realistically work or plan to work on this task - it would be welcome!
For tips how to manage individual work in Phabricator (noisy notifications, lists of task, etc.), see https://phabricator.wikimedia.org/T228575#6237124 for available options.
(For the records, two emails were sent to assignee addresses before resetting assignees. See T228575 for more info and for potential feedback. Thanks!)