+=head1 HISTORY
+
+C<strict 'subs'>, with Perl 5.6.1, erroneously permitted to use an unquoted
+compound identifier (e.g. C<Foo::Bar>) as a hash key (before C<< => >> or
+inside curlies), but without forcing it always to a literal string.
+
+Starting with Perl 5.8.1 strict is strict about its restrictions:
+if unknown restrictions are used, the strict pragma will abort with
+
+ Unknown 'strict' tag(s) '...'
+
+As of version 1.04 (Perl 5.10), strict verifies that it is used as
+"strict" to avoid the dreaded Strict trap on case insensitive file
+systems.
+