Entered an area (launchpad) beyond my skills/knowledge, and feel unable to continue.

OAuth tokens are used to allow other programs to use Launchpad for various purposes. In your case, the token was created when you logged into https://askubuntu.com/ using your Launchpad account. This is normal and nothing to worry about; it doesn't indicate that you've done anything unusual. It just means that askubuntu.com is (for reasons I don't need to go into here) using a slightly odd authentication system that's liable to cause you to get a confusing email when you sign up for it, but that's not your problem.

As far as I can see, you've done nothing wrong, and there's no need to cancel anything or apologise for anything.

However, if you do still want to, you can revoke this individual token at https://launchpad.net/~/+oauth-tokens, or deactivate your entire Launchpad account by following the instructions on https://help.launchpad.net/YourAccount/Closing. Be aware that doing either of these will disable access to your account on askubuntu.com as well, and in particular deactivating your Launchpad account may do things that are hard or impossible to reverse if you change your mind later, so I would advise against doing that if the only reason for it is that you received a confusing email.

Hope this helps; let us know if you need more help.

hi Colin, It didn't so much solve as create more stuff to read before proceeding. I don't want to deactivate my launchpad account because it's all so fascinating, but am unsure if I left myself open to any problems.
So, Not a question per se.Just to clarify that I understand (I'm still plowing through the definition of PGP keys), the token to askubuntu could be to enable a PGP Key by enabling a "handshake" with another member. But to get to that stage the key first goes to ubuntu to get a key's 'fingerprint' to then send to Launchpad who then starts another process before being able to sign the code of conduct ,but then must be backed up in case I lose it, because I'd be in a really bad position. Did I leave anything out? I got lost in the lines of code in the definition description on Wiki. The token says it is to enable the change of some data... I have difficulty locating the exact phrase as I keep losing that page (am also a newbie on a MacBook so negotiating its variety of tabs and redirects is sending me all over the map as pop ups occur with the most innocent of taps).

OAuth tokens have nothing to do with PGP keys; they're both systems that involve cryptography, but that's pretty much where the similarity ends. Studying how PGP keys work won't help you with understanding OAuth tokens.

OAuth provides opaque authorisation tokens that allow you to authenticate to servers that support them without having to provide your username and password, allowing them to be delegated between sites in some circumstances (e.g. askubuntu.com allowing you to log in using your launchpad.net account), and allowing individual tokens to be limited in various ways or revoked individually without having to change your password. There are many more details that are relevant if you're actually implementing OAuth, but from a user point of view that's pretty much all it boils down to.