--- sprintf2.t_orig     2020-10-04 18:24:56 +1100
+++ sprintf2.t  2020-10-04 18:24:37 +1100
@@ -1178,4 +1178,25 @@
     is($off2, 1, "offset after 0");
 }

+# %g formatting was broken on Ubuntu, Debian and perhaps other systems
+# for a long time. Here we verify that no such breakage still exists.
+
+if($Config{nvsize} == 8) {
+    cmp_ok(sprintf("%.54g", 0.3), 'eq', '0.299999999999999988897769753748434595
763683319091796875',
+           "sprintf( \"%.54g\", 0.3 ) renders correctly");
+}
+elsif($Config{nvtype} eq 'long double' && ($Config{longdblkind} == 3 || $Config
{longdblkind} == 4)) {
+    cmp_ok(sprintf("%.64g", 0.3), 'eq', '0.300000000000000000010842021724855044
3400745280086994171142578125',
+           "sprintf( \"%.64g\", 0.3 ) renders correctly");
+}
+elsif($Config{nvtype} eq 'long double' && $Config{longdblkind} >= 5 && $Config{
longdblkind} <= 8) {
+    # oops ... TODO (for double-double)
+else {
+    cmp_ok(sprintf("%.115g", 0.3), 'eq',
+           '0.29999999999999999999999999999999999037035027806382073472011028707
5363407309491758923059023800306022167205810546875',
+           "sprintf( \"%.115g\", 0.3 ) renders correctly");
+}
+
+
 done_testing();