The RSS entry page can retain multiple versions for the same (urlid, link) pair. Normal version history remains strict enough to keep real visible-text changes as separate revisions.
The admin action Purge noisy duplicates for this entry is an explicit cleanup operation. It keeps the newest representative for each meaningful text signature and removes older rows that differ only through noise such as punctuation or changing URLs.
Rows whose meaningful text is empty use strict normalized equality as a safety fallback instead of being merged only because their meaningful hash is empty.
The purge runs with AJAX when JavaScript is available. The result is shown inline and the entry/history card is refreshed without a browser page reload. The same endpoint still supports a normal POST/redirect flow when JavaScript is unavailable.
Large histories are streamed through the cleanup comparison instead of loading every stored content body into application memory at once. This keeps the same comparison behavior while making cleanup practical for entries with many thousands of stored versions.
The operation is scoped to the selected feed ID and entry link before any rows are deleted.