Where in WordPress core is the method or function that reads the style CSS header?

Question

I'm looking for the method or function that reads the style.css file header for the theme.

Answer 1

See this line in the WP_Theme class constructor:

https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-includes/class-wp-theme.php#L348

that calls the get_file_data() function:

https://developer.wordpress.org/reference/functions/get_file_data/

on the style.css file.