Carp (3perl)         - alternative warn and die for modules
Class::MOP::Deprecated (3pm) - Manages deprecation warnings for Class::MOP
diagnostics (3perl)  - produce verbose warning diagnostics
encoding::warnings (3perl) - Warn on implicit encoding conversions
indirect (3pm)       - Lexically warn about using the indirect method call sy...
Moose::Deprecated (3pm) - Manages deprecation warnings for Moose
Package::DeprecationManager (3pm) - Manage deprecation warnings for your dist...
pam_warn (8)         - PAM module which logs all PAM items if called
perllexwarn (1)      - Perl Lexical Warnings
snd_BUG (9)          - give a BUG warning message and stack trace
splain (1)           - produce verbose warning diagnostics
strictures (3pm)     - turn on strict and make all warnings fatal
Test::Warn (3pm)     - Perl extension to test methods for warnings
usb_reset_device (9) - warn interface drivers and perform a USB port reset
vwarn (3)            - formatted error messages
vwarnx (3)           - formatted error messages
warn (3)             - formatted error messages
warnings (3perl)     - Perl pragma to control optional warnings
warnings::register (3perl) - warnings import function
warnx (3)            - formatted error messages