v5.16 => {
new => [
+ ["<code>no feature ${wbr}'array_base'</code>", 'disables <code>$[</code> to alter the 0 index of the first array element or substring character', {bundle => 0, dropped => v5.30}],
['<code>__SUB__</code>', 'current subroutine reference', {feature => 'current_sub'}],
['<code>fc, "\F"</code>', 'unicode foldcase to compare case-insensitively', {feature => 'fc'}],
['<code>"\N{}"</code>', 'automatic <code>use charnames qw( :full :short )</code>'],
v5.18 => {
new => [
+ ['PERL_PERTURB_KEYS=1', 'hash overhaul; order is randomised instead of being semi-repeatable', {eg => 'each %{{%hash}} ne each %{{%hash}}'}],
['<code>${^LAST_FH}</code>', 'last read filehandle (used by <code>$.</code>)'],
['<code>/(?[ a + b ])/</code>', 'regex set operations (character subtraction <code>-</code>, union <code>+</code>, intersection <code>&</code>, xor <code>^</code>)', {experimental => 'regex_sets', stable => v5.36}],
['<code>my sub</code>', 'lexical subroutines (also <code>state</code>, <code>our</code>); buggy before v5.22', {experimental => 'lexical_subs', stable => v5.26}],
v5.26 => {
new => [
+ ["<code><s>use lib '.'</s></code>", 'current directory no longer included in default module search path <code>@INC</code>'],
['<code><<~EOT</code>', 'indented here-docs, strips same whitespace before delimiter in each line'],
['<code>@{^CAPTURE}</code>', q"array of last match's captures, so <code>${^CAPTURE}[0]</code> is <code>$1</code>"],
['<code>//xx</code>', 'extended modifier to also ignore whitespace in bracketed character classes'],