My best guess is that he posted the picture before painting the green one under the yellow. The image was linked in a forum where the author was discussing re-purposing those buttons and the little paint mod.

Planning such a remote is a delicate balance and the worst thing to do is add more buttons to try and cover absolutely every permutation of every device. With the Harmony, they include a number of buttons which are themselves niche at best, such as the page Up/Down, so it makes some sense to re-purpose those first. I mean, I can't recall seeing a device that didn't use the channel buttons for page_up and down where appropriate, making the dedicated buttons completely superfluous in 99.9% of setups.

With their latest keyboard remote it doesn't look like much planning went into it honestly. It looks really slapped together and uncomfortable. I'm sure it will del into the millions though because Logitech has that ability with almost anything. Revue excepted