Most people who frequented phpBB 2 forums have met the Subsilver theme at some point. Wesnoth’s community is not the exception, and the phpBB 3 switch completed by cycholka/Mist in March 2008 during the third-to-last host migration involved switching everyone to Subsilver2, which is the last incarnation of the good old Subsilver. Most of us Wesnoth forumers have become accustomed to the cleanness, quirks and old-school feel of Subsilver2.
However, that will eventually change.
Maintaining patches for mods affecting the forum user and moderator front-ends involves editing three template sets, which are Prosilver (phpBB 3’s new built-in and default style), Subsilver2 and AcidTech, which is Subsilver2-based with some essential layout differences. There are even some mods that don’t provide MODX instructions for Subsilver2, since it’s not essential for approval in the official modifications database to include support for this style that’s most likely going to be dropped in future phpBB release series.
If you take a look at my Projects section you’ll also notice that I’ve needed to write a couple of Subsilver2 hacks in the past to add minor functionality that’s present in the official phpBB 3 “Olympus” forum theme by default. There’s a third custom change in my tree, corresponding to the Quick Reply editor toggle button.