in a database file is useless, because the asterisk in a partial matching
subject key is always followed by a dot.
+When the lookup is done from a string-expansion,
+the variables &$1$& and &$2$& contain the wild and non-wild parts of the key
+during the expansion of the replacement text.
+They return to their previous values at the end of the lookup item.
+
The value &"system"& results in no caching under GnuTLS.
The macro _HAVE_TLS_CA_CACHE will be defined if the suffix for "system"
-is acceptable in configurations for the Exim executvble.
+is acceptable in configurations for the Exim executable.
Caching of the system Certificate Authorities bundle can
save significant time and processing on every TLS connection