What happened?

The "Authentication - Cookie" plugin writes log messages that are hardcoded
as English strings in PHP instead of using language constants from the
plugin's .ini file.

Affected file: plugins/authentication/cookie/src/Extension/Cookie.php

1. "Invalid cookie detected." is passed directly to Log::add().
2. "Failed to delete cookie token for user %s with the following error: %s"
   is built with \sprintf() and passed to Log::add().

Because these strings are not stored in
administrator/language/en-GB/plg_authentication_cookie.ini, they are not
maintainable by the language files and are not exposed to translators on
Crowdin. Other log messages in the same file (e.g. the
PLG_AUTHENTICATION_COOKIE_ERROR_LOG_LOGIN_FAILED message) already do this
correctly using Text::sprintf().

Version

6.2

Expected result

All user-facing / log strings use language constants (Text::_ / Text::sprintf)
defined in the plugin .ini file, so they are translatable via Crowdin.

Actual result

The two log messages are hardcoded in English in Cookie.php and cannot be
translated or maintained through the language files.

System Information

Joomla 6.2-alpha2 (current 6.2-dev branch)

Additional Comments

A fix is straightforward: add the two strings as language keys in
plg_authentication_cookie.ini and replace the hardcoded strings with
Text::_() / Text::sprintf().