[otrs] Where are the Template Modules?

I had a post in a HowTo relating to Event Template Modules, and the current documentation references them: http://otrs.github.io/doc/manual/developer/3.3/en/html/otrs-module-layers.ht... but the location of the source code for them isn't as visible (to me) on github as it was for cvs. Does someone know so I may update my (very old) links?