misc content updates

1 files changed, 10 insertions, 1 deletions

diff --git a/_intro.qmd b/_intro.qmd
index 3730b43..2ed07de 100644
--- a/_intro.qmd
+++ b/_intro.qmd
@@ -86,7 +86,7 @@ by the following early design decisions:
 * The project solely involves freely licensed tools and resources,
   and is itself licensed under Free licences that encourage collaboration.
 
-### Scope limited to use for authoring
+### Scope limited to use for authoring {#sec-phase1}
 
 The scope of this project is to enable annotating while authoring.
 Rendering that makes use of annotations is outside this scope,
@@ -104,6 +104,15 @@ as illustrated in @fig-phase1.
 
 ### Added syntax in the spirit of Markdown {#sec-spirit}
 
+Markdown is a lenient markup language.
+Partly this is derived from Markdown being a superset of HTML,
+which is (or was, when Markdown was introduced) based on SGML
+that by design permits parsers to omit markup they cannot handle
+[@Connolly1994, section "SGML as a Layered Communications Medium"].
+Partly it is due to a deliberate design choice,
+as reflected in the quote introducing this paper:
+The format should be easy to both write and read in source form.
+
 *FIXME: rewrite as more fluent prose*
 
 In the source format of Markdown with annotations...