Your licence
Lost your key, or need to free up one of your three computers. No password — the email you bought with is the whole of it.
Your licence key was emailed to you when you bought it, and it is a long line of text nobody is expected to keep. Put in the address you bought with and it comes again — along with a link to the page holding it, which is how you sign in. That link lasts a day.
Freeing a slot. A licence runs on three of your own computers. If one of them has been wiped, sold, or replaced, its slot is still spent, and the app on that machine is the only other thing that can give it back. That page is the other way.
What is kept. Your address, your licences, and anything you have written to me about them. Not your card — the payment goes through Lemon Squeezy and never touches this site. Nothing about your repositories, ever: the app has no telemetry, and the only thing a support request attaches is version numbers.