Numbers outside of the map [still cluttered]

README.md

@@ -249,10 +249,19 @@ physically clipped, not hidden with masks. Groups `map`, `flights`, and
 with an original single-stroke alphabet: no installed fonts, raster images,
 filled glyphs, or SVG clipping support are required.
 
-Each track has a numeric identifier and a legend entry with UTC dates/times,
-callsign, ICAO identifier, and average reported barometric altitude. For dense recordings, select
+Each track has a numeric identifier and a legend entry with a single UTC date
+and time at the midpoint between its in-map start and end times, callsign,
+ICAO identifier, and average reported barometric altitude labeled `Alt`.
+Flight entries occupy two balanced columns, reading down the left column
+and then down the right. Full start/end times and the barometric altitude
+source remain in SVG metadata. For dense recordings, select
 shorter periods or larger paper. The program fails explicitly if the legend
 does not fit or a track identifier cannot be placed legibly. Flight identifiers
+are placed entirely outside the map border in the extension margin, near an
+entry/exit point, with a vector leader connecting them to the track. Tracks
+entirely inside the map also use margin labels with leaders. Identifiers never
+fall back to positions inside the map; increase `--extension` or select fewer
+tracks if margin space is insufficient. Flight identifiers
 avoid each other; intersections with map geometry or flight paths are not fully
 optimized. Map lines are simplified at 0.05 mm tolerance and identical paths
 deduplicated; physical pen-path travel optimization is left to plotter software.