Feature summary (what you would like to be able to do and where):
https://en.wikipedia.org/wiki/User:Amalthea/culoghelper.js is a useful tool for the CheckUserLog page that makes the timestamp of a check clickable. When clicked it takes the checkuser to the log page with no filters other than a offset of an hour ahead of the timestamp clicked. The script then scrolls you down to the check that you clicked and highlights it in a light red colour.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
This is used on enwiki to find checks that were performed after this check based on the reason being the same.

Benefits (why should this be implemented?):
Moving this to the CheckUser extension would mean that all checkusers on WMF wikis (not just enwiki that have it installed) can use the feature. It would also allow other projects to use this. Moving this to the extension was suggested on checkuser-l.

Extra details
Some adaptation of the code could be done (such as using a class instead of the style HTML attribute for the highlighting), but most of the work will be writing what was already written in PHP instead of JS. The core concepts and some code could be easily copyable over.