For Apple fans, the touchscreen MacBook Pro PROLED XDR tandem OLED display may be the gift that keeps on giving. Obviously, new integrated digitizing technology made the touchscreen possible, but the ultra-thinness of the display tech can also be credited with enabling the return of a beloved MacBook feature.The touchscreen MacBook Pro is the first MacBook in almost a decade to feature an illuminated Apple logo on the back. I've seen it in person, and it somehow looks like polished metal when closed, and then a glowing bright white when open.Apple bringing back the illuminated logo back is directly attributable to the PROLED XDR display. Each pixel in an OLED panel is emissive, which means there's no need for a backlight. Even after Apple made the laptop lid thinner, it still had some room left there — and it turns out there was enough room left to give the Apple logo its own backlight.As improbable as it seems, there's now a dedicated light for the logo, but not for the rest of the screen. And it still doesn't take up extra space (nor eat up measurable energy).Do it for the fans(Image credit: Lance Ulanoff / Future)Why did Apple do this? Well, Apple's not telling us, but it's clearly a nod to the fans. CEO John Ternus tried to tell us the glowing logo was returning in his tiny X tease that showed light shining on the logo, which was on a flat surface. I simply thought it was another way of highlighting the Apple brand, and the big news to come. Granted, I was never that hooked on the old light-up logo.In fact, my strongest memory around the Apple logo on the back of MacBooks is a conversation I had with Ternus when he was still Apple's hardware lead, during which he explained how Apple milled an ultra-thin and shiny stainless steel Apple logo for the MacBook 12 (the rest of the chassis was brushed aluminum). That was a big deal back then, even if it didn't light up(Image credit: Lance Ulanoff / Future)When Ternus revealed that the glowing logo was returning to the new MacBook Pro during the launch presentation ("the logo is back"), the crowd basically lost their collective minds. It's a big deal.The illuminated logo also serves another purpose, instantly telegraphing that you're using a special MacBook Pro — the first with a touchscreen.What Apple is not sharing, though — and it merits further investigation — is how it managed to make the glowing logo look like polished metal when the laptop is closed. It's an engineering secret that I suspect Apple execs and engineers will take to their graves, even after the inevitable teardown.