When any of the fields associated to a form (such as change information or change password) has its content updated (cleared or typed in), the save button for that form changes its color to lighter brighter (or green) to focus attention on what button needs to be pressed to save that form.
Dev Notes:
Changing the color of the button to remind users to save their changes is great. But the UX needs more changes, such as separating the ‘account changes’ vs the ‘profile changes’ and perhaps only making them editable if the user clicks an edit button or something similar.