3 ms·

They needed US stamps.

• crmi 2y ago
  I didn't see any request for a return envelope or stamp. Author decided to include them (unless I missed something).
  • xp84 2y ago
    It seems like common courtesy for me. Given the FSF are providing that service out of altruism, and are not the ones who neglected to give OP the license in the first place, it's only appropriate to not impose upon them to go buy stamps to send an international letter.
    • crmi 2y ago
      What about the paper, ink, labour involved? Why not slip $10 into envelope instead?
      • db48x 2y ago
        De minimis. You only include the extra envelope so that you can write your own address on it. Postage is the only real expense.