There are 2 main types of udev properties: device-specific and port-specific. The port-specific properties are set independently per port (e.g. port type hints set per interface number for a given vid:pid). The device-specific properties apply to all ports in the device. Some of these properties are currently expected in the physical device (e.g. ID_MM_PLATFORM_DRIVER_PROBE) while some others are expected in each port (e.g. the plugin udev tag filters). For the device-specific properties, we should simplify the logic and just assume that they may be given in either the device or the port.
https://lists.freedesktop.org/archives/modemmanager-devel/2017-March/004074.html
Pushed as 00fb9e98f6003f6b167f7d12a895ec3d1402b027 to git master
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.