Some templates have exactly the same TemplateData parameters. For example, a wiki might have 10 different templates for displaying a message box: Template:Note, Template:Warning, Template:Tip, etc. Other templates have very similar, but not identical TemplateData-- say, the same parameters but different defaults.
Rather than create duplicate `<templatedata>` blocks for each template, it would be great to create a single `<templatedata>` block that all the templates share. I realize you could do this by transcluding the same block into multiple templates, but that's tricky for several reasons:
* I suspect the GUI TemplateData editor won't recognize the transclusion. The TemplateData development team has expressed that they don't want to perform additional wikitext parsing (see T124338), and I don't blame them.
* `<templatedata>` blocks are generally surrounded by `<noinclude>`, so there are limits to how much transclusion you can do.
* Two templates with the same `params` information most likely have different `description` information. So how do you share just the `params` between templates?
There are various ways that each author can dream up to accomplish sharing... but what's the best way? Is there a recommended way that will work best with future versions of TemplateData? Please provide guidance -- or direct software support -- for the best practices for templates to share documentation.