William and Flora Hewlett Foundation — Website: https://www.hewlett.org/

Note: While the Wikidata source contains multiple references to hewlett.org URLs (using http:// protocol), it does not explicitly confirm the exact URL 'https://www.hewlett.org/' as the official website. The source references internal pages (about-us, family-history) but does not state the homepage URL. The protocol difference (http vs https) and lack of explicit homepage URL confirmation means this specific claim cannot be verified from the provided source text, even though it strongly suggests the domain is correct.