wp-includes/SimplePie/src/IRI.php:751Set the scheme. Returns true on success, false on failure (if there are any invalid characters).
$schemestring|nullbool public function set_scheme(?string $scheme) { if ($scheme === null) { $this->scheme = null; } elseif (!preg_match('/^[A-Za-z][0-9A-Za-z+\-.]*$/', $scheme)) { $this->scheme = null; return false; } else { $this->scheme = strtolower($scheme); } return true; }One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
$scheme retyped from string to string|null.verified against sourcesrc/wp-includes/SimplePie/src/IRI.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.