Using this feature triggers warnings in the category
C<experimental::smartmatch>.
-The ticket for this feature is
-L<[perl #119317]|https://rt.perl.org/rt3/Ticket/Display.html?id=119317>.
+The ticket for this experiment is
+L<[perl #13173]|https://github.com/Perl/perl5/issues/13173>.
=item Pluggable keywords
-The ticket for this feature is
-L<[perl #119455]|https://rt.perl.org/rt3/Ticket/Display.html?id=119455>.
+Introduced in Perl 5.11.2
See L<perlapi/PL_keyword_plugin> for the mechanism.
-Introduced in Perl 5.11.2
+The ticket for this experiment is
+L<[perl #13199]|https://github.com/Perl/perl5/issues/13199>.
=item Regular Expression Set Operations
Introduced in Perl 5.18
-The ticket for this feature is
-L<[perl #119451]|https://rt.perl.org/rt3/Ticket/Display.html?id=119451>.
-
-See also: L<perlrecharclass/Extended Bracketed Character Classes>
-
Using this feature triggers warnings in the category
C<experimental::regex_sets>.
+The ticket for this experiment is
+L<[perl #13197]|https://github.com/Perl/perl5/issues/13197>.
+
+See also: L<perlrecharclass/Extended Bracketed Character Classes>
+
=item Subroutine signatures
Introduced in Perl 5.20.0
Using this feature triggers warnings in the category
C<experimental::signatures>.
-The ticket for this feature is
-L<[perl #121481]|https://rt.perl.org/Ticket/Display.html?id=121481>.
+The ticket for this experiment is
+L<[perl #13681]|https://github.com/Perl/perl5/issues/13681>.
=item Aliasing via reference
Using this feature triggers warnings in the category
C<experimental::refaliasing>.
-The ticket for this feature is
-L<[perl #122947]|https://rt.perl.org/rt3/Ticket/Display.html?id=122947>.
+The ticket for this experiment is
+L<[perl #14150]|https://github.com/Perl/perl5/issues/14150>.
See also: L<perlref/Assigning to References>
Using this feature triggers warnings in the category
C<experimental::const_attr>.
-The ticket for this feature is
-L<[perl #123630]|https://rt.perl.org/rt3/Ticket/Display.html?id=123630>.
+The ticket for this experiment is
+L<[perl #14428]|https://github.com/Perl/perl5/issues/14428>.
See also: L<perlsub/Constant Functions>
Using this feature triggers warnings in the category
C<experimental::re_strict>.
+The ticket for this experiment is
+L<[perl #18755]|https://github.com/Perl/perl5/issues/18755>
+
See L<re/'strict' mode>
=item The <:win32> IO pseudolayer
-The ticket for this feature is
-L<[perl #119453]|https://rt.perl.org/rt3/Ticket/Display.html?id=119453>.
+Using this feature triggers warnings in the category
+C<experimental::win32_perlio>.
+
+The ticket for this experiment is
+L<[perl #13198]|https://github.com/Perl/perl5/issues/13198>.
-See also L<perlrun>
+See also L<perlrun/PERLIO>
=item Declaring a reference to a variable
Using this feature triggers warnings in the category
C<experimental::declared_refs>.
-The ticket for this feature is
-L<[perl #128654]|https://rt.perl.org/rt3/Ticket/Display.html?id=128654>.
+The ticket for this experiment is
+L<[perl #15458]|https://github.com/Perl/perl5/issues/15458>.
See also: L<perlref/Declaring a Reference to a Variable>
=item There is an C<installhtml> target in the Makefile.
-The ticket for this feature is
-L<[perl #116487]|https://rt.perl.org/rt3/Ticket/Display.html?id=116487>.
+The ticket for this experiment is
+L<[perl #12726]|https://github.com/Perl/perl5/issues/12726>.
-=item Unicode in Perl on EBCDIC
+=item (Limited) Variable-length look-behind
-=item Script runs
+Introduced in Perl 5.30.0.
-Introduced in Perl 5.28.0
+Variability of up to 255 characters is handled.
Using this feature triggers warnings in the category
-C<experimental::script_run>.
+C<experimental::vlb>.
-See also: L<perlre/Script Runs>
+The ticket for this experiment is
+L<[perl #18756]|https://github.com/Perl/perl5/issues/18756>.
-=item Alphabetic assertions
+See also: L<perlre/(*positive_lookbehind:I<pattern>)> and
+L<perlre/(*negative_lookbehind:I<pattern>)>
-Introduced in Perl 5.28.0
+=item Unicode private use character hooks
+
+Introduced in Perl 5.30.0.
+
+This feature is part of an interface intended for internal and experimental
+use by the perl5 developers. You are unlikely to encounter it in the wild.
+
+Using this feature triggers warnings in the category
+C<experimental::private_use>.
+
+The ticket for this experiment is
+L<[perl #18758]|https://github.com/Perl/perl5/issues/18758>.
+
+=item isa infix operator
+
+Introduced in Perl 5.32.0.
Using this feature triggers warnings in the category
-C<experimental::alpha_assertions>.
+C<experimental::isa>.
-See also: L<perlre/Extended Patterns>.
+The ticket for this experiment is
+L<[perl #18754]|https://github.com/Perl/perl5/issues/18754>
=back
=item The <:pop> IO pseudolayer
-See also L<perlrun>
+See also L<perlrun/PERLIO>
Accepted in Perl 5.20.0
Accepted in Perl 5.28.0
+=item Alphabetic assertions
+
+Introduced in Perl 5.28.0
+
+Accepted in Perl 5.32.0
+
+=item Script runs
+
+Introduced in Perl 5.28.0
+
+Accepted in Perl 5.32.0
+
=back
=head2 Removed features