In English, "To whom it may concern" is a generic starter to a letter implying that the letter is addressed to anyone for whom the letter is relevant.
For a bit of context, I had to ask someone in France for a document confirming my workplace, and was thinking how I would word such a document in English. In English I would have started with "To whom it may concern" whereas the document I was given used a different approach "ATTESTATION", but it did get me thinking!