If you would like to set a static, non-changing, IP Address on your Raspberry Pi, you will need to modify the "headless" file, adding an IP Address, Gateway, and Netmask, to the file for the configurations to work properly(see samples configs below).

IPADDR=[IP Address of Raspberry Pi]

GATEWAY=[IP Address of router/gateway]

If "RESIZE" is in the "headless" file, the root filesystem will be expanded to the maximum size of the sd card via the service rootfs-resize. If "SWAP"(requires the value in megabytes) exists in the "headless" file, a swap file will be created of the specified size, and then activated.