docs: drop hand-kept --derive figures from tools

tests/test_doc_pages.py

@@ -466,5 +466,17 @@ class ToolsRunOnTheStatedFloor(unittest.TestCase):
         self.assertFalse(self._runtime_unions(ast.parse("mask = flags | other")))
 
 
+class DeriveFiguresLiveWithTheTool(unittest.TestCase):
+    """tools.md gave --derive about 90 s and 67 entries while its --help said
+    about 35 s: two hand-kept figures for one run, measured at 33 s."""
+
+    def test_the_page_carries_no_duration_or_count(self):
+        paragraph = next(
+            p for p in _page("tools.md").split("\n\n") if "`--derive` reads" in p
+        )
+        self.assertNotRegex(paragraph, r"\d+ ?s\b|\d+ entries")
+        self.assertIn("derivable.json", paragraph)
+
+
 if __name__ == "__main__":
     unittest.main()

wiki/tools.md

@@ -864,13 +864,12 @@ python scripts/provenance_report.py --json     # full report
 ```
 
 A catalog lists chips as they come off the board, the collection often holds
-the image an emulator reads. `--derive` reads the collection (about 90 s) and
+the image an emulator reads. `--derive` reads every file of the collection and
 marks a missing entry DERIVABLE when a held file produces its sha1 by halving,
 quartering, splitting into even and odd bytes or 16-bit words (byte-swapped
 or not), swapping bytes, mirroring, or joining two files of one directory.
 The Amiga Kickstart chip pairs and TOSEC's split C64 and VES ROMs are found
-this way: 67 entries on the current snapshots, recorded in `derivable.json`
-by pipeline step 1b.
+this way. Pipeline step 1b records what it finds in `derivable.json`.
 
 | Catalog | Acquisition | Notes |
 |---------|------------|-------|