@raimane Hmm, if I install https://chromewebstore.google.com/detail/share-link-via-email/ejdbkikfbnnhmachnnomjfgjbgkcnjkb, goto https://example.com/, right-click on the page, goto "Share link via email" and choose "Share page via email", a Thunderbird compose window opens up with "Example Domain" as the subject and https://example.com/ in the body.