pfSense

On the Interface Configuration / Track IPv6 Interface:
Suggest change “IPv6 Prefix ID” to “IPv6 Subnet ID” or “IPV6 Prefix Subnet ID”

Reason:
I have seen some confusion by those new to IPv6 that this field is referring to the subnet ID. This might be clearer if it is more in agreement with "RFC 4291 IP Version 6 Addressing Architecture" terminology.

2.5.4.  Global Unicast Addresses
   The general format for IPv6 Global Unicast addresses is as follows:

|         n bits         |   m bits  |       128-n-m bits         |
   ---------------------------------+----------------------------+
| global routing prefix  | subnet ID |       interface ID         |
   ---------------------------------+----------------------------+
   where the global routing prefix is a (typically hierarchically-
   structured) value assigned to a site (a cluster of subnets/links),
   the subnet ID is an identifier of a link within the site, and the
   interface ID is as defined in Section 2.5.1.

Also in Section 2.

In this document, fields in addresses are given a specific name, for
   example, "subnet".  When this name is used with the term "ID" for
   identifier after the name (e.g., "subnet ID"), it refers to the
   contents of the named field.  When it is used with the term "prefix" 
   (e.g., "subnet prefix"), it refers to all of the address from the
   left up to and including this field.