+<h3> CUSTOM COMMANDS</h3>
+<pre>
+ If the given command is not known to notmuch, notmuch tries to execute
+ the external <b>notmuch-<subcommand></b> in ${PATH} instead. This allows users
+ to have their own notmuch related tools to be run via the notmuch com‐
+ mand. By design, this does not allow notmuch's own commands to be over‐
+ ridden using external commands.
+</pre>
+
+<h3> OPTION SYNTAX</h3>
+<pre>
+ All options accepting an argument can be used with '=' or ':' as a sep‐
+ arator. Except for boolean options (which would be ambiguous), a space
+ can also be used as a separator. The following are all equivalent:
+
+ notmuch --config=alt-config config get user.name
+ notmuch --config:alt-config config get user.name
+ notmuch --config alt-config config get user.name
+</pre>
+