A lot log messages: "Deprecated event type for ..."

my log is flooded with this message:

[no app in context] Info: Deprecated event type for \OCP\Files::postCreate: Symfony\Component\EventDispatcher\GenericEvent is used

GET /apps/mail/

It seams to come from the mail app.

it’s not from Mail

I thought because β€œGET /apps/mail/”
Do you know where it could come from?

The code that emits this event. You can likely use textual search to find the source