wp-includes/fonts/class-wp-font-library.php:107Gets all the font collections available.
array public function get_font_collections() { return $this->collections; }Introduced in 6.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/fonts/class-wp-font-library.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.