wp-includes/customize/class-wp-customize-header-image-control.php:198Gets current image source.
string|null public function get_current_image_src() { $src = $this->value(); if ( isset( $this->get_url ) ) { $src = call_user_func( $this->get_url, $src ); return $src; } }Introduced in 3.9.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
string|void to string|null.verified against sourcesrc/wp-includes/customize/class-wp-customize-header-image-control.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.