I feel really stupid but that's what happened.
I went to the ToolForge registration page: https://toolsadmin.wikimedia.org/register/ and registered with my WikiMedia account. The login name was auto-generated so I quickly looked and went further.
You'll see later why it's important: when I've completed the registration process, there was no email to confirm my altered email address or just about registration success (yes, I wanted to celebrate).
When I tried to login here: https://toolsadmin.wikimedia.org/auth/login/ I realized that I remember my password perfectly but I'm not sure if the login was with a space character, an underscore, without anything... And there is no trace where I could look it up. What do I do in such a situation? Trying to register again requires me to create another WikiMedia account which not something I wish to do.
I eventually found the character I was unsure about but:
- the missing login recovery procedure is an issue
- also, it might be useful to be able to
- login with an email associated to account
- and to have a registration email received in the inbox
- and to be able to use a password recovery link at the login page (there is no such).