Undocumented Apple Wallet cases

Here's a list of discussions and topics about undocumented things of Apple Wallet. The contents are not only of this repository but also from other websites.

• Event Tickets automatically expire after around a year, when expirationDate, nor voided, nor relevantDate(s) are provided (#261)
• HIG (Human Interface Guidelines) is not updated about how fields are displayed in generic passes (passkit-visual-designer/#30)
• labelColor or foregroundColor are used interchangebly on some passes based on the background color, to improve readability (passkit-visual-designer/#30)