Think of #submission as a filter on the wider porn caption caption archive: same submission pool, but slimmed down to the exact register you searched for.
The page pulls in submission-tagged captions, plus caption GIFs where submission is a secondary tag, plus roleplay posts whose title text overlaps with the submission keyword — three sources into one feed.
Because engagement counts (likes, saves, shares) are live per post, the page keeps sorting itself even without editorial intervention — the top of the feed reflects real porn captions demand today, not last month.
As more creators publish under #submission, this page rebuilds itself daily with fresh title, alt, caption and tag combinations — meaning what you saw yesterday is not what you'll see tomorrow.