JetBrains has just improved their tapestry plugin to use the specfied tapestry_x_x.xsd when indicating errors in .tml files.
<t:extension-point id="<id>"> is flagged with a missing required attribute name (according to the xsd), however the ExtensionPointToken / SaxTemplateParser seems to expect an attribute called "id" being specified, using "name" results in a tapestry exception:
Caused by: org.apache.tapestry5.ioc.internal.util.TapestryException: Element <extension-point> does not support an attribute named 'name'. The only allowed attribute name is 'id'.
I guess the easiest fix is to alter the xsd's to match the actual parser code to prevent breaking existing tapestry applications.
This is a trivial fix and could be a nice thing to have in place before releasing 5.4