Piwigo/include/smarty/docs/programmers/api-variables/variable-default-modifiers.md

$default_modifiers

This is an array of modifiers to implicitly apply to every variable in a template. For example, to HTML-escape every variable by default, use array('escape:"htmlall"'). To make a variable exempt from default modifiers, add the 'nofilter' attribute to the output tag such as {$var nofilter}.