Background
We want to do this as part of work to implement Special:IPContributions (in the CheckUser extension), which shows contributions from temporary accounts editing from the same IP address or range. (See T358852: [Epic] Display temporary account contributions on Special:Contributions for IP addresses and IP ranges for full context.)
SpecialIPContributions needs to be able to show existing contributions (from the revision table) or deleted contributions (from the archive table).
SpecialIPContributions uses IPContributionsPager, which extends ContributionsPager, from MediaWiki core. ContributionsPager does most of the work to filter and display the relevant revisions. Most of the functionality provided by ContributionsPager would be useful for deleted (archived) contributions too.
(Eventually, it may be possible to make DeletedContribsPager extend ContributionsPager. That is beyond the scope of this current work.)
What needs doing
By making a few field names configurable, and by ensuring we fetch the revisions from the correct table, ContributionsPager can handle both deleted contributions and normal contributions.