Is it permissible to inform a poor person that the food is an expiation for a specific sin, or does that fall under the category of openly committing a sin? And is expiation considered an act of charity?

There is no objection to giving zakat or expiations to their rightful recipients without informing them. In fact, it is not appropriate to inform them of the type of expiation or its reason, because expiation is so named because it expiates and conceals the sin, so it is not fitting for it to be a cause for its declaration. The poor person does not have the right to ask about the reason for the expiation. For those who will not accept it unless informed, they must be told that it is merely an expiation, without explaining the matter. If they insist, then one should seek someone else. As for those who accept without asking, there is no harm in giving it to them without informing them. Sheikh Ibn Uthaymeen was asked about the ruling on giving zakat without informing, and he replied that there is no harm in it if the recipient usually accepts it. However, if the recipient is someone who does not accept it, then they must be informed.

Expiation differs from charity in several ways, including: - Expiation is obligatory, while charity is voluntary. - It is not permissible to give expiation to a non-believer, whereas charity is permissible for a peaceful non-believer.