docs: Update docs

docs/markdown/IDE-integration.md

@@ -405,6 +405,17 @@ of a node type or the removal of a key) are unlikely and will be
 announced in the release notes.
 
 
+# JSON Reference manual
+
+In additional to the online [Reference manual](Reference-manual.md), Meson also
+offers the manual as JSON file. The content of this file is generated from the
+same source as the online documentation. The two versions are thus identical
+in content.
+
+This JSON document is attached to every Meson release since *0.60.0*. The JSON
+schema is defined by the class structure given in
+[`jsonschema.py`](https://github.com/mesonbuild/meson/blob/master/docs/refman/jsonschema.py)
+
 # Existing integrations
 
 - [Gnome Builder](https://wiki.gnome.org/Apps/Builder)

docs/refman/templates/root.mustache

@@ -5,8 +5,14 @@ render-subpages: false
 
 # Reference manual
 
-This is the root page of the Meson reference manual. All functions
+This is the root page of the online Meson reference manual. This
-and methods are documented in detail in the following subpages:
+manual is also available in a more machine readable format as a
+JSON documented attached to every release since *0.60.0*. See our
+[IDE integration](IDE-integration.md) documentation for more
+information.
+
+All functions and methods are documented in detail in the
+following subpages:
 
 ## Elementary types