I saw this on my breakfast cereal box (in the US) and looked it up. A company called Navilens made this to help visually impaired people with things like street signs, etc... neat!
EDIT TO ADD: Haha, I forgot I am on lemmy so we're discussing the technology and licensing issues, instead of focusing on how this might improve the lives of visually impaired people.
I'm disappointed the London underground is using this proprietary thing, rather than QR codes, which have existed forever and are an open standard.