Where the tags come from — the front matter of each published article, nothing added here.
What is left out — 180 tags sit on a single piece. We do not open a page for those; the tag still shows on the article, it just does not become an address of its own.
Spellings folded together — the same subject written two ways (k-pop and kpop, say) becomes one address, and the tag page says which spellings it gathered.