* Write array literals with one item per line. This makes diffs which add or remove items far easier to interpret, and makes merging such changes feasible. And it looks nicer too.
* Use line breaks to show the logical structure of your code. This enhances readability. Bring similar elements in a list into alignment, in order to reveal the differences between those elements at a glance.
* Removed a fun game of spot-the-difference in AbuseFilterHistoryPager::getQueryInfo(). If I want fun games I'll play UFO:AI.
* Moved some oddly placed assignments (in expressions) to their own statements: such assignments reduce readbility.
-- Introduce tagging of individual changes (revisions, logs, and on recentchanges). The tags are customisable, and currently settable by the Abuse Filter and by the TorBlock extension. The tags can be styled on the various pages on which they appear.
-- Introduces a schema change, three new tables (valid_tag, change_tag, and tag_summary).
* Allow matching on the changes made in an edit (added/removed lines, etc)
* Improve display of variables in details view - standardise the table size, add white-space: pre, font-family: monospace.
* Improve modifiers: add htmlencode/htmldecode/urlencode/urldecode.
* Add 'abuse filter tools', currently consisting of a testing ground for the modifiers. In future, may include facilities for testing filters against user contributions, recent changes, or other sources.