Apple is using "Myriad Pro Set" as a web font. I'm assuming that somehow we can now purchase a license to use Myriad Pro as a web font.
Adobe says the font is available for web use. But, the only info they provide is a link to Typekit (owned by Adobe), which does offer "Myriad Pro" but Typekit's Myriad Pro is a serif font -- not the sans-serif that Apple has popularized.
Does anyone know anything about this?
For a subscription fee at Adobe Fonts, the web font is available.
As for the fonts being different (serif vs. sans-serif), here is a side-by-side comparison of the font off apple.com (left) and the font off the Adobe page you linked to (right):
As you can see, there is no difference between the two, at least with this "G" character, and I couldn't find any other noticeable differences.