Inconsistency in usage "Colour" and "Color"

There is an inconsistency in the usage of "color" and "colour" - Not really a bug, but thought it should be highlighted - Given the maturity of the project to ptoentially "break" older styles and mods it may not be worth it, but anyway - heres an example, from mcp_warn:

'USER_COLOR' => (!empty($user_row['user_colour'])) ? $user_row['user_colour'] : '',