When you log in to a Microsoft account in the launcher, you see this screen:
You may wish to create a custom OAuth application to remove the reference to "SKCraft Launcher"
Creating a custom OAuth application
Read Microsoft's quick-start guide. Note that you want to make an app for "Mobile and desktop applications" - you set this in the dropdown next to the redirect URI.
Navigate to the Authentication tab on the left of the app's management page, and add a new redirect URI to http://localhost:
Scroll down and ensure the required features are enabled:
Personal Microsoft accounts only
Live SDK support: yes
Allow public client flows: yes
Put the client ID of your new app in launcher.properties
Test the login process; you will have to authorize the new app!