I started this project to make vim-tagbar work with Elm. I use tagbar to get an overview of my source files (especially python); I like how it presents the scope of nested tags. I wanted that overview of my Elm modules too. ctags-elm got me started but exuberant ctags doesn’t let you define scoped tags in config files. Universal Ctags does. So now, after some discussion, the Ctags part of vim-tagbar-ctags-elm is a Universal Ctags optlib. Optlib lets you define a set of command line options in a file, and then generate c source from them so they ca be compiled into ctags executable.
This was always in the plan. Next tagbar itself, maybe?