Add layout source file tagging on nodes, enable module by default, etc ...
A feature I've always wanted when viewing the page layout XML dump is the ability to see source files after the merge. This update re-writes Mage_Core_Model_Layout_Update::getFileLayoutUpdatesXml to inject an x-layout-file attribute into every child node of each layout file's handles.
This way, I have a better idea of which layout file is actually affecting the page.
This is a tricky method to extend, because there are no convenient dispatch events to hook into my target entry point. So in my best effort I tried to write some compatibility checks that would allow CE versions 1.4 - 1.9 to be supported.
Also cleaned up the formatting in config files a bit, and enabled the module by default.
If you don't think the main feature belongs in this module, that's OK. I'll just keep using my fork :) But I thought this makes for a good addition, especially since you're already re-writing the layout update model.