wp-includes/category-template.php:288Retrieves category description.
$categoryintoptional0stringfunction category_description( $category = 0 ) { return term_description( $category );}Introduced in 1.0.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/category-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.