Dear gang,

It appears that internal opentype feature tlig is not supported in the  
export. For current purposes this is not critical; but not sure if this is  
intentional or a bug, so reporting it here.

===============
\setupbackend[export=yes]

\starttext

\startchapter[title=The tlig feature]
\startparagraph
In \TeX\ it is still common to use two keyboard dashes to obtain an  
en-dash. An en dash is used to indicate a number range, e.g., 1785--1906.

In \TeX\ it is still common to use three keyboard dashes to obtain an  
em-dash. An em-dash is used to indicate a prominent parenthesis---in  
modern usage the en-dash is becoming more popular for this task---as well  
as between the end of an epigraph and its author.

In \Context\ there is a dedicated control sequence for the en-dash. An  
en-dash is used to indicate a number range, e.g., 1785\endash{}1906.

In \Context\ there is a dedicated control sequence to obtain an em-dash.  
An em-dash is used to indicate a prominent parenthesis\emdash{}in modern  
usage the en-dash is becoming more popular for this task\emdash{}as well  
as between the end of an epigraph and its author.
\stopparagraph
\stopchapter
\stoptext
===============

Thanks and best wishes
Idris
-- 
Idris Samawi Hamid
Professor of Philosophy
Colorado State University
Fort Collins, CO 80523