When looking at the tags on Physics Meta, I've noticed that many tags do not have the tag-excerpt. To my surprise, after I clicked on some of them I found out that they have a tag-info. (In fact, it is also displayed in the tooltip also on the tag-page.) When hovering over "history" link in the tag-info, I get a tooltip saying "This is the default initial version."
It seems that for some tags the tag-info is automatically created when a new meta site is created. (The only ones I found were the mandatory tags and moderator-only tags - see also: The imported tag-info for default tags is ignored in revision history.)
Is this behavior intentional? I think tag-excerpt for these tags should be displayed in the same way as the tag-excerpts for other tags are.
Here is a screenshot of what I see on the tags page:
Here is what I see when I check the tag-info for (discussion):
And here is the tag-info for (status-completed):