Background

IP addresses are not shown by default on Special:IPInfo.

For users who have the checkuser-temporary-account right, add a column on the left with buttons to reveal the IP address for each row:

Technical considerations

How to add the column
Although the checkuser-temporary-account right is from CheckUser, we can check it from IPInfo here, since the feature depends on CheckUser to look up the IP addresses.

How to know which IP each row refers to
Since this table is on Special:Contributions, it should only search the cu_changes table for IP addresses. (E.g. we shouldn't include information about IP addresses used for private events such as logging in here, since that's beyond the scope of Special:Contributions and would give checkuser-like information to users of this page, which has a much lower access threshold than CheckUser.)

We can therefore associate each row with a revision ID (if several revision IDs are used by one IP address, we only need one), in order to look up which IP address the row refers to when clicking "reveal IP"