+my $groups = do 'keyboard/altgr/groups.inc.pl';
+$groups->{mode} = {
+ '' => 'option-shifted ⌥',
+ 'm' => 'Ω greek prefix ⌥m',
+ 'M' => '√ maths prefix ⌥M',
+ $presymbol => "$rows{$presymbol} symbol prefix ⌥$presymbol",
+};
+for my $m (qw' m M ', $presymbol) {
+ $groups->{def}->{''}->{$m} = "g1 mode$m";
+ $groups->{mode}->{$m} //= "mode $m";
+ $groups->{def}->{$m} = {
+ (map {s/^.//r => 'g0'} grep {/^\Q$m/} keys %rows),
+ $m => 'g1 mode',
+ };
+}
+$groups->{flag}->{g1} = ['mode' => "switch to an alternate set of keys"];
+