It’s “18 Å”, not “18A” (which would be 18 Amperes). I would think that Intel would be keen to not be confused with either Ampere Computing or Nvidia’s Ampere GPU architecture.
How would I know in advance that this gives Å and not Æ or à or Ā or  or À or Á or Ä? And how would I type the other ones? Don't have a Mac, so I actually don't know how it is supposed to be done.
> How would I know in advance that this gives Å and not Æ or à or Ā or  or À or Á or Ä?
The same way you know in advance that CTRL+SHIFT+@ gives you Å in Windows?
Both Windows and Mac can display an on-screen keyboard that will display the character that will be output if you press a key along with modifier keys like CTRL or Option.