That is a return receipt. No guarantees, as returning them is up to the recipient. But that is how the email specification is written, so there is no enforcing it, unlike with Signed receipts for snail mail.
Ma proposition 🤔 est de pouvoir seulement savoir si un message envoyé d'un PC a été ouvert, comme par exemple sur la messagerie WhatsApp pour tel mobile. Cette option (en "paramètres") serait sous forme d'une couleur ou d'un style de caractère, comme le gras pour un message reçu et ouvert.
Ce retour d'info (feedback ?), moins formel que l'accusé de réception qui demande l'agrément actif du destinataire,serait souvent utile 🙃.
Je soumets humblement cette idée à toutes et tous. Vive Mozilla et Thunderbird.
Hello, and sorry, I speak French.
My proposal 🤔 is to only be able to know if a message sent from a PC has been opened, such as on WhatsApp messaging for such a mobile. This option (in "parameters") would be in the form of a color or a character style, such as bold for a message received and opened.
This feedback (feedback?), less formal than the acknowledgment of receipt which requires the active approval of the recipient, would often be useful 🙃.
I humbly submit this idea to everyone. Long live Mozilla and Thunderbird.