How to get the ID of your Nintendo Account's Mii

To get your Nintendo Account's Mii ID, go to https://accounts.nintendo.com/ and log into an account with a Mii, and then open any image of it in a new tab. E.G., right click (or long hold touch on mobile) the circle with your Mii in it above User Info or in the top right corner and press the appropriate menu option. The URL should look somewhat like this if you grab the right one:
https://cdn-mii.accounts.nintendo.com/2.0.0/mii_images/3e5328d61bd4860d/c6e36c183112cd1be0eed159f5a49d0b.png?type=face&width=140&bgColor=3BAADEFF
The value you want is between "/miis/" and "/image/" in the URL, so mine would be "3e5328d61bd4860d". Nothing else in that URL matters. You can then import that data into my Mii render grabber or Closedverse/Openverse or whatever else we decide to use this for. That's it.
UPDATE: You can also find this in the Mii Studio by going to edit your Mii and then finding the Mii ID in the URL (example: "3e5328d61bd4860d" in the URL "https://studio.mii.nintendo.com/miis/3e5328d61bd4860d/edit?client_id=d9a620d8bb417787").