USR369 asked for a complete inventory of all backend HTML pages to find duplicates/overlap -- confirmed AUDIT.php (referenced in SOP-AUDIT.md Pass 7) was never actually built (404), and it would not have answered this question anyway (it checks comment-map/standards compliance, not content duplication). Built a new tool, systems/html-inventory-api.php: recursively scans DOCUMENT_ROOT for .html and HTML-rendering .php files (excludes old-zips archive, backups/, .trash/, backend/tmp/), strips script/style/comments before comparing (avoids false matches on shared boilerplate), computes an md5 of normalized text for exact-duplicate grouping and 5-word-shingle Jaccard similarity for overlap detection. Live run: 302 pages, 15 exact-duplicate groups, 62 overlap pairs (0.45 threshold). Real findings: Tech[30] apps/ folder has the Library/Navigator/Script-Library/Android-Library/scripts tools each duplicated 2-5x across apps/, apps/Database_PREV/, and root frontend/30-Tech/ with inconsistent PREVIOUS_[name]_MM-DD-YY naming (not the platform CURRENT/PREVIOUS/trash standard). systems/30-tech/android-scripts.php, server-scripts.php, win-scripts.php are byte-identical and ALL still titled "Windows Scripts" -- looks like copy-paste-without-customization, not just old-copy clutter. Gym Logger has index.html and index-v6.10.html both live in the same folder with identical body content (382KB/385KB, comment-map-only size difference) -- relates to the already-open "v6.00 rebuild from CC[100] unconfirmed" item. Also flagged as expected/non-issue: all 11 system hub index.php pages score 0.90+ similar to each other by design (shared template) -- not a real duplication problem. One tool limitation found and disclosed: a group of mostly-JS-driven pages (db-viewer.php, file-editor.php, server-map.php, verify_lib.php, master-list.php, page-viewer.php) false-matched together with genuinely-empty stub files because stripping script/style leaves them with near-zero static text -- flagged in the report as not a real finding. Full report delivered as a markdown file to USR369.