Background
Special:DeletedContributions shows a user's contributions from pages that were deleted. Like Special:Contributions, a temporary user's deleted contributions page might have many entries, from different IP addresses.
IP reveal buttons are added to Special:Contributions, so they should be added to Special:DeletedContributions too.
Technical background
IP reveal buttons are added to most pages wherever there are temporary user links. They are currently not added to Special:DeletedContributions because there are no user links. There are no user links on Special:Contributions either, but CheckUser has some custom code to add buttons to Special:Contributions.
This currently can't be re-used for Special:DeletedContributions because the HTML structure is quite different.
What needs doing
After T370438: Improve feature parity between Special:Contributions and Special:DeletedContributions, it should be possible to add IP reveal buttons to Special:DeletedContributions by loading temporaryaccount/SpecialContributions.js (with minimal modifications) from dispatcher.js.

