The Japanese counterpart of North America's Super NES Classic Edition launched later than the console did in other regions. The filing was actually outed by a Japanese trademark bot on Twitter, and the illustration that appears with the filing is simply one of the original Game Boy.
A trademark application this broad is, of course, no indication that Nintendo has any plans to release a Classic Mini Game Boy but it's interesting timing given the recent release of the SNES Classic Mini.
Nintendo has recently found tremendous success through the re-release of classic consoles in a new format.
Nintendo's nostalgia-fuelled Super NES Classic has been out for less than two weeks, but it's already been hacked to add more games and custom backgrounds.
According to a translation from Kotaku, the application covers everything from "home video game console" programs as well as "programs for smartphones", "smartphone cases", "smartphone covers", as well as "key holders", "necklaces", and "watches" - but nothing specific relating to either GameBoy Mini or GameBoy Classic.
The trademark was filed on September 15, and included this Game Boy image. Perhaps it's thinking about giving the Game Boy the same Classic treatment? Fans were also reminded that the miniature console from Nintendo only has 300 megabytes of space, so they will have to make their choices carefully. There were 1,049 games released for the handheld, so Nintendo shouldn't have any trouble choosing a couple of dozen.