Hi @theaht123,
This is a god question, and I've tried to check a few different areas and haven't found much either. From what I've pieced together from a few different areas, "content tag" may refer to html content, meaning then the tool is successfully returning content to Canvas. The only issue with that definition is that the parameter needs to be included in a launch, so there isn't really a way to know if content is going to be returned while doing the launch. Practically, I've checked a few external tools with module placements in our instance and they seem to populate that parameter if I include it. Are you having some issues where it's not working for you, or were you just asking out of curiosity as you perhaps build or install a tool?
-Chris
