diff --git a/3.1.0/reference.json b/3.1.0/reference.json
index 97ab82f..af4284d 100644
--- a/3.1.0/reference.json
+++ b/3.1.0/reference.json
@@ -2701,6 +2701,14 @@
                 "doc": "In case of `line` placement, offsets a text position a number of pixels parallel to its actual path. In case of `grid` placement, reduces or expands the polygon area. Positive values move the line left or expand the polygon, negative values move it right or shrink the polygon (relative to the directionality of the line or polygon winding).",
                 "status": "unstable"
             }
+            "extend": {
+                "css": "text-extend",
+                "type": "float",
+                "expression": true,
+                "default-value": 0.0,
+                "default-meaning": "",
+                "doc": "A temporary path will created that extends both the starting and final segments of a line by the given distance (starting and final segments are the same for lines with a single segment). The text will be rendered on this extended line, i.e. text will extend beyond the line length. Option is only valid with placement-line."
+            },
         },
         "building": {
             "default": {
diff --git a/README.md b/README.md
index 734b331..9ce6e49 100644
--- a/README.md
+++ b/README.md
@@ -4,9 +4,7 @@
 
 It is useful for building parsers, tests, compilers, and syntax highlighting/checking for languages.
 
-[![Build Status](https://travis-ci.org/mapnik/mapnik-reference.svg)](https://travis-ci.org/mapnik/mapnik-reference)
-
-Default branch is `gh-pages` which is displayed at http://mapnik.org/mapnik-reference
+Default branch is `gh-pages`, which is displayed at http://mapnik.org/mapnik-reference
 
 ## Versioning
 
@@ -20,13 +18,13 @@ and the next targeted release of Mapnik.
 
 ## Meaning
 
-The structure of the file is as such:
+The structure of `reference.json` is:
 
 * `version`: the version of Mapnik targeted. Same as the containing directory.
 * `style`: properties of the `Style` XML element
 * `layer`: properties of the `Layer` XML element
-* `symbolizers/*`: properties that apply to **all** symbolizers
-* `symbolizers/symbolizer`: properties that apply to **each** type of symbolizer
+* `symbolizers`: properties that apply to all symbolizers (removed from version 2.1.0 onwards)
+* `symbolizers/`_\<symbolizer\>_: properties that are specific to a given symbolizer
 * `colors`: named colors supported by Mapnik. see `include/mapnik/css_color_grammar.hpp`
 
 ### Property stability
@@ -38,6 +36,7 @@ then the `status` is `stable`. Possible values are:
 - **deprecated:** `property` should not be used and will be removed in upcoming major version of Mapnik
 - **experimental:** `property` should not be used and may change, be re-named, or disappear at any time
 
+`datasources.json` separately details the properties of the possible data sources (since version 2.3.0). 
 
 ## Using
 
@@ -82,5 +81,5 @@ Tests require python and node.js:
 
 ## Users
 
-* [carto.js](https://github.com/mapbox/carto)
-* Mapnik itself (the util/validate-mapnik-instance.py is used to check binding consistency like in [#1427](https://github.com/mapnik/mapnik/issues/1427))
+* [carto.js](https://github.com/cartocss/carto)
+* [Mapnik documentation](http://mapnik.org/mapnik-reference)